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Michael O. Kelleher, Gamaliel Tan, Roger Sarjeant, and Michael G. Fehlings

Object

Despite the growing use of multimodal intraoperative monitoring (IOM) in cervical spinal surgery, limited data exist regarding the sensitivity, specificity, and predictive values of such a technique in detecting new neurological deficits in this setting. The authors sought to define the incidence of significant intraoperative electrophysiological changes and new postoperative neurological deficits in a cohort of patients undergoing cervical surgery.

Methods

The authors conducted a prospective analysis of a consecutive series of patients who had undergone cervical surgery during a 5-year period at a university-based neurosurgical unit, in which multimodal IOM was recorded. Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) were determined using standard Bayesian techniques. The study population included 1055 patients (614 male and 441 female) with a mean age of 55 years.

Results

The IOM modalities performed included somatosensory evoked potential (SSEP) recording in 1055 patients, motor evoked potential (MEP) recording in 26, and electromyography (EMG) in 427. Twenty-six patients (2.5%) had significant SSEP changes. Electromyographic activity was transient in 212 patients (49.6%), and 115 patients (26.9%) had sustained burst or train activity. New postoperative neurological deficits occurred in 34 patients (3.2%): 6 had combined sensory and motor deficits, 7 had new sensory deficits, 9 had increased motor weakness, and 12 had new root deficits. Of these 34 patients, 12 had spinal tumors, of which 7 were intramedullary. Overall, of the 34 new postoperative deficits, 21 completely resolved, 9 partially resolved, and 4 had no improvement. The deficits that completely resolved did so on average 3.3 months after surgery. Patients with deficits that did not fully resolve (partial or no improvement) were followed up for an average of 1.8 years after surgery.

Somatosensory evoked potentials had a sensitivity of 52%, a specificity of 100%, a PPV of 100%, and an NPV of 97%. Motor evoked potential sensitivity was 100%, specificity 96%, PPV 96%, and NPV 100%. Electromyography had a sensitivity of 46%, specificity of 73%, PPV of 3%, and an NPV of 97%.

Conclusions

Combined neurophysiological IOM with EMG and SSEP recording and the selective use of MEPs is helpful for predicting and possibly preventing neurological injury during cervical spine surgery.

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Michael O. Kelleher, Rashid K. Al-Abri, David V. Lenihan, and Michael A. Glasby

Object

While pulsed electromagnetic stimulation has been shown to enhance peripheral nerve regeneration, the effect of a static magnetic field on nerve repair is less clear. The aim of this study was to establish what effect an imposed exogenous static magnetic field has on peripheral nerve regeneration after transection and repair.

Methods

Three groups of six adult sheep were used. The first group acted as normal controls. In the second group, the median nerve was divided and immediately repaired by entubulation within a “controlled-release” biodegradable glass tube. In the third group, small magnets were applied to the sides of the biodegradable glass tubes before the median nerve was repaired using these magnetic tubes. The sheep were allowed to recover and were reexamined 10 months later. The animals underwent comprehensive morphometric (cross-sectional morphometry and measurement of internodal lengths), electrophysiological (determinations of stimulated jitter, maximum conduction velocity, refractory period, and F waves), and isometric tension (isometric twitch and tetanic tension) assessments.

Conclusions

Exogenously applied static electromagnetic fields do not enhance peripheral nerve regeneration.

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Michael O. Kelleher, Dylan J. Murray, Anne McGillivary, Mahmoud H. Kamel, David Allcutt, and Michael J. Earley

Object

The neurobehavioral morbidity of nonsyndromic trigonocephaly is incompletely understood. The purpose of this study was twofold: first, to assess the degree of developmental, educational, and behavioral problems in patients with nonsyndromic trigonocephaly and second, to establish whether patients with mild degrees of trigonocephaly had a lower frequency of such problems.

Methods

The authors performed an observational study of the frequency of developmental, educational, and behavioral problems in 63 children with trigonocephaly at the National Craniofacial Centre in the Republic of Ireland between 1989 and 2004. The parents of the children completed a follow-up questionnaire. Thirty percent of patients had a mild form of trigonocephaly and were treated conservatively. The remainder underwent surgical correction. Speech and/or language delay was reported in 34% of the children. Thirty-three percent of the children needed to be assessed by a school psychologist, and 47% were receiving remedial or resource hours within the school system. Twenty percent of children required a special needs classroom assistant because of behavioral issues, and 37% of parents expressed concerns about their child’s behavior. There were no statistically significant differences between children treated with surgery and those who had a mild deformity and were treated conservatively.

Conclusions

Nonsyndromic trigonocephaly is associated with a high frequency of developmental, educational, and behavioral problems. The frequency of these problems is not related to the severity of the trigonocephaly.

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Michael O. Kelleher, Nasir A. Quarishi, Gamaliel Tan, Abhijit Guha, and Eric M. Massicotte

✓In this report, the authors describe a unique case of intermittent high cervical cord compression caused by a prolapsing neurofibroma at the C1–2 level. This 21-year-old man with known neurofibromatosis Type 1 presented with a mass between the anterior arch of the atlas and the odontoid peg, causing atlantoaxial dissociation and cord compression. The cervicomedullary compression appeared to be caused in part by the neurofibroma but also by the abnormal alignment and thickening of the ligaments between the clivus and C-2. Preoperative imaging repeated on the morning of surgery revealed that the atlantoaxial dissociation had reduced with relief of cord compression and the lesion prolapsed inferiorly. The authors discuss this unusual lesion and describe the associated operative findings and surgical management.