Spine Journal: Article on Safe Thoracic Pedicle screw placedment

Thoracic pedicle screw placements especially the upper thoracic levels do not have specific  muscle innervation making it difficult to test pedicle screws, in other words it is not as discrete as you can do a test on for example Deltoid (Cervical) or Tibialis anterior (lumbar). The following article though

Spine (Phila Pa 1976). 2012 

Safe pedicle screw placement in thoracic scoliotic curves using t-EMG: stimulation threshold variability at concavity and convexity in apex segments.

de Blas G, Barrios C, Regidor I, Montes E, Burgos J, Pizá-Vallespir G, Hevia E.

Source

Department of Clinical Neurophysiology, Hospital Ramón y Cajal, Madrid, Spain.

Abstract

STUDY DESIGN:

A cross-sectional study of nonconsecutive cases (level III evidence).

OBJECTIVE:

In a series of young patients with thoracic scoliosis who were treated with pedicle screw constructs, data obtained from triggered electromyography (t-EMG) screw stimulation and postoperative computed tomographic scans were matched to find different threshold limits for the safe placement of pedicle screws at the concavity (CC) and convexity (CV) of the scoliotic curves. The influence of the distance from the medial pedicle cortex to the spinal cord on t-EMG threshold intensity was also investigated at the apex segment.

SUMMARY OF BACKGROUND DATA:

Whether the t-EMG stimulation threshold depends on pedicle bony integrity or on the distance to neural tissue remains elusive. Studying pedicle screws at the CC and CV at the apex segments of scoliotic curves is a good model to address this issue because the spinal cord is displaced to the CC in these patients.

Mar 15;37(6):E387-95. doi: 10.1097/BRS.0b013e31823b077b.

Scoliosis & More

The following article on Scoliosis provide a comprehensive look at what is scoliosis and related surgical interventions. Though, hard to explain the causes for scolisosis, efforts to understand this disease provided us more knowledge. Intraoperative neuromonitoring is extensively used in scoliosis correction surgical procedures.

Scoliosis and Proprioception
Robert Schleip
Published in Rolf Lines, Vol. 28, No.4 (Fall 2000)
Most types of scoliosis are classified as ‘idiopathic scoliosis’ which means that the reasons for this type of rotational deformity of the spine are yet unknown. Nevertheless there are all kinds of assumptions, beliefs and anectdotal reports available in the alternative health community concerning the main causes and driving factors.........................


Central Nervous System Processing in Idiopathic Scoliosis
By Jerry Larson, M.A.
Diplomate, American Board of Neurophysiological Monitoring

"The clinical manifestations of idiopathic scoliosis are well known, yet its causes remain unclear. Several factors have been proposed, including abnormal structural elements of the spine, dysfunctional spinal musculature, genetic factors, alterations of collagen metabolism, and abnormalities of the central nervous system. The most promising investigations appear to implicate the central nervous system, especially those areas involved with postural equilibrium. Spinal cord reflexes play an integral role in the maintenance of posture. These complex polysynaptic segmental reflexes are regulated by a variety of descending suprasegmental systems, by peripheral afferent impulses and within the spinal ....................

Neuromuscular Scoliosis- Intraoperative Neuromonitoring: Challenges!

Nature Clinical Practice Neurology (2007) 3, 318-319
doi:10.1038/ncpneuro0502
Received 7 December 2006 Accepted 5 April 2007
Published online: 8 May 2007

Intraoperative monitoring during spinal surgery for neuromuscular scoliosis
Michael G Fehlings* and Michael O Kelleher
Correspondence *Suite 4WW-446, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada Email michael.fehlings@uhn.on.ca

This article has no abstract so we have provided the first paragraph of the full text.

The avoidance of iatrogenic neurological injury is of paramount importance during spinal surgery, and multimodality intraoperative monitoring using a combination of MEPs, SSEPs and electromyographic (EMG) signals is increasingly used in this setting.1, 2 During corrective procedures for neuromuscular scoliosis, however, the successful application of intraoperative monitoring is a challenge

, particularly in the most severely deformed and neurologically compromised patients.3 Difficulties in obtaining reliable baseline recordings of conventional (cortical and subcortical) SSEPs and transcranial MEPs in patients with neuromuscular scoliosis has prompted the use of an epidural electrode to record spinal SSEPs and evoke neurogenic MEPs.

Neuromuscular Scoliosis?- Intraoperative Neuromonitoring!!

Michael G Fehlings* and Michael O Kelleher

Correspondence 

*Suite 4WW-446, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada

Email michael.fehlings@uhn.on.ca

This article has no abstract so we have provided the first paragraph of the full text.

• The avoidance of iatrogenic neurological injury is of paramount importance during spinal surgery, and multimodality intraoperative monitoring using a combination of MEPs, SSEPs and electromyographic (EMG) signals is increasingly used in this setting.^{1, 2} During corrective procedures for neuromuscular scoliosis, however, the successful application of intraoperative monitoring is a challenge, particularly in the most severely deformed and neurologically compromised patients.³ Difficulties in obtaining reliable baseline recordings of conventional (cortical and subcortical) SSEPs and transcranial

  MEPs in patients with neuromuscular scoliosis has prompted the use of an epidural electrode to record spinal SSEPs and evoke neurogenic MEPs.

You do Spine surgery and Do not monitor nerves..Why?

Neuro monitoring (a.k.a.: Neurophysiologic Intraoperative Monitoring) may be one of the most exciting and important €œold€ innovations to come into spine and neuro surgery in decades.

Think of it, what surgeon would dare operate without blood gas monitoring? Or blood pressure monitoring?

So why operate without nerve monitoring?

We recently talked with Debra Zacharko, who teaches neuro monitoring for NeuroMatrix in Atlanta. She described a case in which one of her clients scheduled a straightforward laminectomy and declined to use neuro monitoring. €œSo, I told him that I'€™d perform the monitoring for free,€ said Zacharko, €œand when I showed him the wave form tapes

he was amazed to see how much nerve irritation there is even in a simple laminectomy.€