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George M. Ghobrial, Thana Theofanis, Bruce V. Darden, Paul Arnold, Michael G. Fehlings and James S. Harrop


Unintended durotomy is a common occurrence during lumbar spinal surgery, particularly in surgery for degenerative spinal conditions, with the reported incidence rate ranging from 0.3% to 35%. The authors performed a systematic literature review on unintended lumbar spine durotomy, specifically aiming to identify the incidence of durotomy during spinal surgery for lumbar degenerative conditions. In addition, the authors analyzed the incidence of durotomy when minimally invasive surgical approaches were used as compared with that following a traditional midline open approach.


A MEDLINE search using the term “lumbar durotomy” (under the 2015 medical subject heading [MeSH] “cerebrospinal fluid leak”) was conducted on May 13, 2015, for English-language medical literature published in the period from January 1, 2005, to May 13, 2015. The resulting papers were categorized into 3 groups: 1) those that evaluated unintended durotomy rates during open-approach lumbar spinal surgery, 2) those that evaluated unintended durotomy rates during minimally invasive spine surgery (MISS), and 3) those that evaluated durotomy rates in comparable cohorts undergoing MISS versus open-approach lumbar procedures for similar lumbar pathology.


The MEDLINE search yielded 116 results. A review of titles produced 22 potentially relevant studies that described open surgical procedures. After a thorough review of individual papers, 19 studies (comprising 15,965 patients) pertaining to durotomy rates during open-approach lumbar surgery were included for analysis. Using the Oxford Centre for Evidence-Based Medicine (CEBM) ranking criteria, there were 7 Level 3 prospective studies and 12 Level 4 retrospective studies. In addition, the authors also included 6 studies (with a total of 1334 patients) that detailed rates of durotomy during minimally invasive surgery for lumbar degenerative disease. In the MISS analysis, there were 2 prospective and 4 retrospective studies. Finally, the authors included 5 studies (with a total of 1364 patients) that directly compared durotomy rates during open-approach versus minimally invasive procedures. Studies of open-approach surgery for lumbar degenerative disease reported a total of 1031 durotomies across all procedures, for an overall durotomy rate of 8.11% (range 2%–20%). Prospectively designed studies reported a higher rate of durotomy than retrospective studies (9.57% vs 4.32%, p = 0.05). Selected MISS studies reported a total of 93 durotomies for a combined durotomy rate of 6.78%. In studies of matched cohorts comparing open-approach surgery with MISS, the durotomy rates were 7.20% (34 durotomies) and 7.02% (68), respectively, which were not significantly different.


Spinal surgery for lumbar degenerative disease carries a significant rate of unintended durotomy, regardless of the surgical approach selected by the surgeon. Interpretation of unintended durotomy rates for lumbar surgery is limited by a lack of prospective and cohort-matched controlled studies.

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R. John Hurlbert, Charles H. Tator, Michael G. Fehlings, Greg Niznik and R. Dean Linden

✓ Although the assessment of spinal cord function by electrophysiological techniques has become important in both clinical and research environments, current monitoring methods do not completely evaluate all tracts in the spinal cord. Somatosensory and motor evoked potentials primarily reflect dorsal column and pyramidal tract integrity, respectively, but do not directly assess the status of the ventral funiculus. The present study was undertaken to evaluate the use of evoked potentials, elicited by direct cerebellar stimulation, in monitoring the ventral component of the rodent spinal cord. Twenty-nine rats underwent epidural anodal stimulation directly over the cerebellar cortex, with recording of evoked responses from the lower thoracic spinal cord, both sciatic nerves, and/or both gastrocnemius muscles. Stimulation parameters were varied to establish normative characteristics. The pathways conducting these “posterior fossa evoked potentials” were determined after creation of various lesions of the cervical spinal cord.

The evoked potential recorded from the thoracic spinal cord consisted of five positive (P1 to P5) and five negative (N1 to N5) peaks. The average conduction velocity (± standard deviation) of the earliest wave (P1) was 53 ± 4 m/sec, with a latency of 1.24 ± 0.10 msec. The other components followed within 4 msec from stimulus onset. Unilateral cerebellar stimulation resulted in bilateral sciatic nerve and gastrocnemius muscle responses; there were no significant differences (p > 0.05) in the thresholds, amplitudes, or latencies of these responses elicited by right- versus left-sided stimulation. Recordings performed following creation of selective lesions of the cervical cord indicated that the thoracic response was carried primarily in the ventral funiculus while the sciatic and gastrocnemius responses were mediated through the dorsal half of the spinal cord. It is concluded that the posterior fossa evoked potential has research value as a method of monitoring pathways within the ventral spinal cord of the rat, and should be useful in the study of spinal cord injury.

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Alpesh A. Patel, Peter G. Whang, Andrew P. White, Michael G. Fehlings and Alexander R. Vaccaro

The process of publishing scientific research can be hampered by potential pitfalls for journals and researchers alike; the definition and determination of authorship, legal documentation, data accuracy, and disclosure of financial conflicts of interest are all examples. In the current article, the authors discuss the challenges related to scientific medical writing and provide updated recommendations for both the prevention and management of these issues.

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Julio C. Furlan and Michael G. Fehlings

Cardiovascular complications in the acute stage following traumatic spinal cord injury (SCI) require prompt medical attention to avoid neurological compromise, morbidity, and death. In this review, the authors summarize the neural regulation of the cardiovascular system as well as the pathophysiology, diagnosis, and management of major cardiovascular complications that can occur following acute (up to 30 days) traumatic SCI. Hypotension (both supine and orthostatic), autonomic dysreflexia, and cardiac arrhythmias (including persistent bradycardia) are attributed to the loss of supraspinal control of the sympathetic nervous system that commonly occurs in patients with severe spinal cord lesions at T-6 or higher. Current evidence-based guidelines recommend: 1) monitoring of cardiac and hemodynamic parameters in the acute phase of SCI; 2) maintenance of a minimum mean arterial blood pressure of 85 mm Hg during the hyperacute phase (1 week after SCI); 3) timely detection and appropriate treatment of neurogenic shock and cardiac arrhythmias; and 4) immediate and adequate treatment of episodes of acute autonomic dysreflexia. In addition to these forms of cardiovascular dysfunction, individuals with acute SCIs are at high risk for deep venous thrombosis (DVT) and pulmonary embolism due to loss of mobility and, potentially, altered fibrinolytic activity, abnormal platelet function, and impaired circadian variations of hemostatic and fibrinolytic parameters. Current evidence supports a recommendation for thromboprophylaxis using mechanical methods and anticoagulants during the acute stage up to 3 months following SCI, depending on the severity and level of injury. Low-molecular-weight heparin is the first choice for anticoagulant prophylaxis in patients with acute SCI. Although there is insufficient evidence to recommend (or refute) the use of screening tests for DVT in asymptomatic adults with acute SCI, this strategy may detect asymptomatic DVT in at least 9.4% of individuals who undergo thromboprophylaxis using lowmolecular- weight heparin. Indications and treatment of DVT and acute pulmonary embolism are well established and are summarized in this review. Recognition of cardiovascular complications after acute SCI is essential to minimize adverse outcomes and to optimize recovery.

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Anatomy of the sacral nerve roots: clinical implications for neural repair

Michael G. Fehlings and Allyson Tighe

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Factors predicting the resectability of intramedullary spinal cord tumors and the progression-free survival following microsurgical treatment

Michael G. Fehlings and David Mercier

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Importance of sagittal balance in determining the outcome of anterior versus posterior surgery for cervical spondylotic myelopathy

Michael G. Fehlings and Randolph Gray

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Michael G. Fehlings and Julio C. Furlan

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En bloc resection for metastatic spinal tumors: is it worth it?

Michael G. Fehlings and Doron Rabin