Somatosensory evoked potential (SSEP) monitoring allows for assessment of the spinal cord and susceptible structures during complex spinal surgery. It is well validated for the detection of potential neurological injury but little is known of surgeon's responses to an abnormal trace and its effect on neurological outcome. We aimed to investigate this in spinal deformity patients who are particularly vulnerable during their corrective surgery. Our institutional neurophysiology database was analysed between 1st October 2005 and 31st March 2010. Monitoring was performed by a team of trained neurophysiology technicians who were separate from the surgical team. A significant trace was defined as a 50% reduction in trace amplitude or a 10% increase in signal latency. Patients suffering a significant trace event were examined post-operatively by a Consultant Neurologist who was separate from the surgical team.Introduction
Methods
Evidence suggests that intra-operative spinal cord monitoring is sensitive and specific for detecting potential neurological injury. However, little is known about surgeons' responses to trace changes and the resultant neurological outcome. To examine the role of intra-operative somatosensory evoked potential (SSEP) monitoring in the prevention of neurological injury, specifically sensitivity and specificity, and whether the abnormalities were reversible.Introduction
Objective
To evaluate the current biomechanical and clinical evidence available on the use and effectiveness of lumbar interspinous devices Literature review A PubMed search was done using the following key words: interspinous implants, interspinous devices, interspinous spacers, dynamic stabilization, X-stop, Coflex, Wallis, DIAM. The abstracts of all the articles were reviewed. Further critical analysis was done of the relevant articles. Special emphasis was given to those articles pertaining to biomechanical and clinical results. A total of 50 articles were found, 18 of them also related to the effect of spacers on the biomechanics of the spine. 25 articles were on the X-stop device. However, level I evidence is lacking. Only two prospective randomized controlled trials have been done and these were on the X-Stop device. Analysis of current evidence suggests a potential beneficial effect of lumbar interspinous spacers in select group of patients. However, further level I evidence is required to justify their widespread use for all the proposed indications. The results of the ongoing trials are keenly awaited.
Non-dysraphic intradural spinal cord lipomas are very rare lesions and the management remains controversial. We present our experience with five cases, review the literature and propose guidelines for their management The case notes of the patients were retrospectively reviewed. An extensive literature search was done, and the relevant articles were analyzed. Between January 2004 and April 2009, we operated on five cases of non-dysraphic intradural spinal cord lipomas. The age at presentation ranged from 17 years to 52 years (mean 32.2). Minimum follow up was 6 months and maximum follow up 5 years. All patients underwent decompression with a laminectomy/ laminoplasty and debulking. The dura was primarily closed in one patient. All patients had regular clinical and radiological follow-up with serial MRI scans. Neurological improvement was noted in all patients. There was significant residual tumour on the MRI scan in all patients. Guidelines for management were formulated on the basis of our experience and literature review. The aim of surgery should be adequate decompression with preservation of neural structures. Aggressive debulking should be avoided. Onset of any neurological symptoms/signs, bowel or bladder symptoms or intractable local symptoms should be an indication for surgery.
To describe a modification of the existing technique for C2 translaminar screw fixation that can be used for salvage in difficult cases. Bilateral crossing C2 laminar screws have recently become popular as an alternative technique for C2 fixation. This technique is particularly useful in patients with anomalous anatomy, as a salvage technique where other modes of fixation have failed or as a primary procedure. However, reported disadvantages of this technique include breach of the dorsal lamina and spinal canal, early hardware failure and difficulty in bone graft placement due to the position of the polyaxial screw heads. To address some of these issues, a modified technique is described. In this technique, the upper part of the spinous process of C2 is removed and the entry point of the screw is in the base of this removed spinous process. From October 2008 to March 2009, 6 patients underwent insertion of unilateral translaminar screws using our technique. The indications were: basilar invagination(three cases), C1/C2 fracture (two cases), tumour (one case). Age varied from 22 to 81 years (mean 48 years). All patients had post-operative x-ray and CT scan to assess position of the screws. Mean follow-up was 6 months. The screw position was satisfactory in all patients. There were no intraoperative or early postoperative complications. Our modification enables placement of bone graft on the C2 lamina and is also less likely to cause inadvertent cortical breach. Because of these advantages, it is especially suitable for patients with advanced rheumatoid arthritis with destruction of the lateral masses of C2 or as part of a hybrid construct in patients with unilateral high riding vertebral artery. This technique is not suitable for bilateral translaminar screw placement.
