Introduction. 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. Objective. 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. Methods. 2953 consecutive complex spine operations (male 36% female 64%, median age 25yrs) prospectively performed using spinal cord monitoring at a single institution (2005–2009). All traces and neurophysiological events were prospectively recorded by the neurophysiology technician. All patients with a significant neurophysiology event were examined clinically by a neurologist, separate from the spinal surgery team. Significant trace abnormality was defined as a decrease in signal amplitude of 50% or a 10% increase in latency. Timing of trace abnormality, surgeon's response and prospective neurological outcome were recorded. Sensitivity, specificity, positive/negative predictive value were calculated. A Chi-squared test was performed to assess the impact of intervention on neurological outcome (p < 0.05). Results. 2953 operations involving SSEP monitoring were performed and 106 recorded a significant trace abnormality. This most often occurred during instrumentation and the most common reaction was adjustment of metalwork. SSEP monitoring had a sensitivity of 100%, specificity 97.3%, PPV 24%, NPV 100%. There were 79 false positives and no false negatives in this series. Chi-squared test was not significant (p=0.18) suggesting that intervention might not affect neurological outcome in this cohort. Conclusions. Triggering events are uncommon and the development of a persistent neurological deficit is rare with an incidence of 0.85% in this series of 2953 operations. In the majority of cases detection of a monitoring abnormality prompts a corrective reaction by the surgeon. Of those with an abnormal trace 76% were neurologically normal at follow up

Background:. Spinal deformity surgery carries the risk of loss of neurological function which may be permanent. Although the overall the incidence is low it is much higher in complex congenital deformities or those with pre-existing myelopathy. Intra-operative spinal cord monitoring allows this risk to be reduced by providing feedback to the surgeon while the corrective manoeuvres are performed. Although ideally a trained technician with multimodal monitoring is recommended, it is often not an option in a resource limited environment and surgeon operated technology is used. Aim:. to evaluate the use of surgeon operated trans-cranial motor evoked potentials (tcMEP) in spinal deformity surgery. Methods:. A retrospective review was conducted on a single surgeon series of 108 consecutive cases utilising the NIM system (Medtronic). Percutaneous needles were employed in the scalp, both hands and feet to allow the upper limbs to act as controls. Forty-nine patients were 13 years old or less, 47 were 14–18, and 12 adults. The cohort consisted of 54 AIS, 27 neuromuscular scoliosis, 14 congenital, 2 old TB and 11 miscellaneous. The vast majority were posterior based procedures. Results:. In 4 cases initial traces could not be obtained. One was a severe myelopathy and further efforts to monitor were abandoned. In one case the anaesthetist had broken protocol and once converted to TIVA the traces improved. Two others were poor initially but improved as the case progressed. In 8 cases intra-operative traces were lost. One was thought to be due to hypothermia and the patient woke intact. Two were unrelated to surgical intervention and recovered spontaneously with patients waking intact. Four cases deteriorated during the corrective manoeuvre (one delayed) and recovered with reduction of correction. One case required removal of instrumentation after repeated loss each time rods were inserted and awoke with a weak leg but recovered and was re-operated two weeks later. Conclusion:. Surgeon operated tcMEP's allows feedback in terms of safety of deformity correction with a 100% negative predictive value and an 8% incidence of signal loss during correction allowing immediate remedial action

Objective. Posterior vertebral column resection (PVCR) is indicated in the management of severe rigid spine deformities. It is a complex surgical procedure and is only performed in a few spine centres due to the technical expertise required and associated risk. The purpose of this study is to review the indications, surgical challenges and outcomes of patients undergoing PVCR. Methods. 12 patients with severe spinal deformities who underwent PVCR were retrospectively reviewed after a follow-up of 2 years. Surgery was performed with the aid of motor evoked spinal cord monitoring and cellsaver when available. The average surgical duration was 310 minutes (100–490). The average blood loss was 1491 ml (0–3500). The indication for PVCR was gross deformity and myelopathy which was due to congenital spinal deformities and one case of old tuberculosis. Clinical records and the radiographic parameters were reviewed. Results. Kyphosis of an average of 72 degrees was corrected to 28 degrees. The associated scoliosis was corrected from an average of 49.2 to 21.2 degrees. Ten patients improved neurologically to ASIA D and E. One patient deteriorated markedly, required revision with no initial improvement but reached ASIA E at 6 months after surgery. Four patients had associated syringomyelia. All were re-scanned at 1 year. The three with small syrinx's demonstrated no progression on MRI and the large syrinx resolved completely. In addition to the neurological deterioration, complications included 1 right lower lobe pneumonia. Conclusion. PVCR is an effective option to correct complex rigid kyphoscoliosis. In addition it allows excellent circumferential decompression of the cord and neurological recovery. When the congenital scoliosis is associated with syringomyelia with no other cause evident, it may allow resolution of the syrinx. Key words: Posterior vertebral column resection, severe spinal deformities, myelopathy, syringomyelia. NO DISCLOSURES