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Hyper Smash
Showing posts with label Pedicle screws. Show all posts
Showing posts with label Pedicle screws. Show all posts

Wednesday, January 30, 2013

Vascular Complications During Thoracic Pedicle Screw Placement: What?. Is this even Possible, yes!.

Surgery insight: During surgical performance or surgical procedures and providing patient care, there is nothing like oh you mean that?, well that is very simple or take for granted in a casual way, one must show at most attention and care in every small to big steps, so do the neuromonitoring and anesthesia professionals, you can be of great help to surgeon when you detect changes or unusual activity that can get surgeons attention right away. Ofcourse for surgeons, there is no room for error but absolutely there is no room for Oh I have done 1000s of surgery, pricking a nerve or artery during my pedicle screw insertion is not going to happen, oh well, it did. The following paper describes a case and death of a patient two weeks after the surgery, so be diligent.
While reading this article :Thoracic pedicle screw placement: Free-hand technique  by Yongjung J. Kim, Lawrence G. Lenke regarding Scoliosis and thoraci pedicle screw placement, I came across the two back reference that startled me, an important and interesting reference about how vascular complications can occur by careless pedicle screw placement?..
Vascular complications 
22.Heini P, Scholl E, Wyler D, Eggli S. Fatal cardiac tamponade associated with posterior 
spinal instrumentation. A case report. Spine 1998;23:2226–30.  
Heini et al[22] described a case of fatal cardiac tamponade that
was due to a prick injury of the right coronary artery by a Kirschner
Neurology India | December 2005 | Vol 53 | Issue 4
CMYK517 517 Kim et al: Thoracic pedicle screw placement
wire. The injury was confirmed by autopsy after the patient died
12 days after surgery.
14. Suk SI, Kim WJ, Lee SM, Kim JH, Chung ER. Thoracic pedicle screw fixation in 
spinal deformities: are they really safe? Spine 2001;26:2049–57.   
Suk et al [14] described a case of an over­penetrated screw causing irritation of the thoracic aorta resulting in severe chest pain.
 25. Minor ME, Morrissey NJ, Peress R, Carroccio A, Ellozy S, Agarwal G, et al. 
Endovascular treatment of an iatrogenic thoracic aortic injury after spinal 
instrumentation: case report. J Vasc Surg 2004;39:893–6
 Recently Minor et al [25] reported endovascular  treatment of an iatrogenic aortic injury by misplaced thoracic pedicle screw at T5. 
I have not yet read all these three papers, I will comment further after I go through them all.

Friday, April 16, 2010

Pedicle Screws & Triggered EMGs!

Spine (Phila Pa 1976). 2010 Jan 15;35(2):E43-8.

Usefulness of electromyography compared to computed tomography scans in pedicle screw placement.
Duffy MF, Phillips JH, Knapp DR, Herrera-Soto JA.
STUDY DESIGN: This is a retrospective analysis of 30 pediatric deformity surgeries. OBJECTIVE: The purpose of this study was to evaluate the accuracy of neuromonitoring in comparison to postoperative computed tomography scans for pedicle screw position. SUMMARY OF BACKGROUND DATA: Triggered electromyography potentials in aiding the placement of lumbar pedicle screws are considered useful; however, this method is less accepted in thoracic screw placement. METHODS: Thirty pediatric deformity surgeries were reviewed. All screws were placed using fluoroscopic assistance. Electromyography data were obtained on all screws. Every patient underwent postoperative computed tomography scanning. Computed tomography scans were assessed by all authors, and each screw was classified. Sensitivity, specificity, negative predictive value, and likelihood ratios were determined for the cut-off value of an electromyography > or =6 mA. RESULTS: A total of 329 screws were reviewed. No complications occurred. An overall accuracy of 93% was obtained. No retained screw had greater than 2 mm medial pedicle wall breach. Nine screws were removed intraoperatively due to medial breach. The mean electromyography potential for all classes of screws was not statistically different (P > 0.1). The negative predictive value of the test was 0.92 in the thoracic spine and 0.93 in the lumbar spine. The negative likelihood ratios were 0.96 and 0.35 for the thoracic and lumbar spines respectively, and the positive likelihood ratio was 1.4 for the thoracic spine and 12.5 for the lumbar spine. CONCLUSION: Thoracic and lumbar pedicle screws are safe surgical options in the treatment of pediatric scoliosis. Comparison of electromyography potentials and postoperative computed tomography scans showed no statistically significant difference for all classes of screws. The likelihood ratio for electromyography testing was more clinically significant in the lumbar spine. A triggered electromyography value greater than or equal to 6 mA has a high likelihood of that screw being in the "safe zone." However, there is no true electromyography cut-off value that guarantees accurate placement and avoidance of neurologic injury.