Benefit of Intraoperative Neurophysiological Monitoring in a Pediatric Patient with Spinal Dysmorphism, Split Cord Malformation, and Scoliosis

Intraoperative neurophysiological monitoring in scoliosis surgery: literature review of the last 10 years

INTRODUCTION

Patients with spinal deformities undergoing corrective surgery are at risk for iatrogenic spinal cord injury (SCI) and subsequent neurological deficit. Intraoperative neurophysiological monitoring (IONM) allows early detection of SCI which enables early intervention resulting in a better prognosis. The primary aim of this literature review was to search if there are threshold values of TcMEP and SSEP in the literature that are widely accepted as alert during IONM. The secondary aim was to update knowledge concerning IONM during scoliosis surgery.

METHOD

PubMed/MEDLINE and Cochrane library electronic databases were used to search publication from 2012 to 2022. The following keywords were used: evoked potential, scoliosis, surgery, intraoperative monitoring and neurophysiological. We included all studies dealing with SSEP and TcMEP monitoring during scoliosis surgery. Two authors reviewed all titles and abstracts to identify studies that met the inclusion criteria.

RESULTS

We included 43 papers. Rates of IONM alert and neurological deficit varied from 0.56 to 64% and from 0.15 to 8.3%, respectively. Threshold values varied from a loss of 50 to 90% for TcMEP amplitude, whereas it seems that a loss of 50% in amplitude and/or an increase of 10% of latency is widely accepted for SSEP. Causes of IONM changes most frequently reported were surgical maneuver.

CONCLUSION

Concerning SSEP, a loss of 50% in amplitude and/or an increase of 10% of latency is widely accepted as an alert. For TcMEP, it seems that the use of highest threshold values can avoid unnecessary surgical procedure for the patient without increasing risk of neurological deficit.

Elongated conus medullaris, sacral agenesis and scoliosis- a case report of a patient with trisomy 19q and monosomy 7q

BACKGROUND

Both progression of scoliosis following completion of growth, and the combination of low mental retardationand the conspicuous sagittal clinical and radiographic abnormalities suggest a secondary genesis of the scoliosis according to a genetic aberration.

CASE DISCRIPTION

In the outpatient department, an 18-year-old girl presents with scoliosis and mild mental retardation. Radiography findings demonstrate a sacral agenesis and the consecutively performed MRI a conus depression. Due to the symptom constellation, a genetic syndrome was suspected. Genetic diagnostics revealed a trisomy 19q and monosomy 7q. Usually, deletions of the subtelomer 7q show a phenotype with growth retardation, facial anomalies and intellectual deficit, trisomy of the subtelomer 19q growth retardation, atypical ears, short neck and intellectual deficit with delayed development. The further clinical radiological and neurological examination showed no evidence of a tethered cord syndrome. The correction of scoliosis was carried out under intraoperative neurophysiological monitoring without neurologic complications.

CONCLUSIONS

In the presence of dysplastic sacral changes and accompanying elongated conus medullaris in patients with scoliosis, it is always necessary to think of rare chromosome aberrations and to initiate appropriate diagnostics before surgery. The intraoperative neurophysiological monitoring is strongly recommended, due to a morphologically not fully-excludable tethered cord syndrome.

Spinal Surgery With Electrically Evoked Potential Monitoring and Monopolar Electrocautery: Is Prior Removal of a Cochlear Implant Necessary?

: Transcranial electric stimulation to generate motor evoked potentials in lower limb muscles is the standard technique used to monitor spinal cord efferent pathways during surgical correction for spinal deformities. Monopolar electrical cauterization is also used by default in the thoracic and lumbar area of the spine during this kind of surgery to prevent major blood loss. Owing to the high levels of current used, both techniques are considered contraindicative if the patient has a cochlear implant (CI). Here, we present a CI patient who underwent corrective spinal fusion surgery for a severe kyphoscoliotic spinal deformity on whom both techniques were used without any negative effects on the CI function. A major improvement in sagittal body balance was achieved with no loss in implant-aided hearing levels. These results add to reports that CI manufactures should review their evidence underlying recommendations that transcranial electric stimulation and upper thoracic monopolar electrical cauterization are high risk for CI users, possibly initiating verification studies.