The effect of spinal osteotomies on spinal cord tension and dural buckling: a cadaveric study

Abstract

<jats:sec> <jats:title>OBJECT</jats:title> <jats:p>The standard surgical release of a tethered cord may result in recurrent scar formation and occasionally be associated with retethering. The application of spinal shortening procedures to this challenging problem potentially can reduce tension on the retethered spinal cord while minimizing the difficulties inherent in traditional lumbosacral detethering revision. Although spinal shortening procedures have proven clinical benefit in patients with a recurrent tethered cord, it is unclear how much shortening is required to achieve adequate reduction in spinal cord tension or what impact these osteotomies have on dural buckling.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>The authors calculated mean values from 4 human cadavers to evaluate the effect of 3 different spinal shortening procedures—Smith-Petersen osteotomy (SPO), pedicle subtraction osteotomy (PSO), and vertebral column resection (VCR)—on spinal cord tension and dural buckling. Three cadavers were dedicated to the measurement of spinal cord tension, and 3 other cadavers were devoted to myelography to measure dural buckling parameters.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>The SPO was associated with a maximal decrease in spinal cord tension of 16.1% from baseline and no dural buckling with any degree of closure. The PSO led to a mean maximal decrease in spinal cord tension of 63.1% from baseline at 12 mm of closure and demonstrated a direct linear relationship between dural buckling and increasing osteotomy closure. Finally, VCR closure correlated with a mean maximal decrease in spinal cord tension of 87.2% from baseline at 10 mm of closure and also showed a direct linear relationship between dural buckling and increases in osteotomy closure.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>In this cadaveric experiment, the SPO did not lead to appreciable tension reduction, while a substantial response was seen with both the PSO and VCR. The rate of tension reduction may be steeper for the VCR than the PSO. Adequate tension relief while minimizing dural buckling may be optimal with 12–16 mm of posterior osteotomy closure based on this cadaveric experiment.</jats:p></jats:sec>

Retethering : A Neurosurgical Viewpoint

“…With a cadaveric tethered cord study, Grande et al 16) demonstrated that a 15-25 mm thoracolumbar subtraction osteotomy effectively lowered the tension on neural structures. In another cadaveric study by Safain et al 35) , 12-16 mm shortening of vertebral column by posterior osteotomy was optimal for adequate tension relief and the minimization of dural buckling.…”

Neuro-vaskuläre Komplikationen bei komplexen Korrektureingriffen − Ursachen, Prävention, Systemlösungen

“…7) [42]. Eine Studie von Safain et al [43] am Kadaver-Modell kam zu dem Schluss, dass mit einer spinalen Verkürzung von 12 -16 mm ein geeigneter Kompromiss aus spinal entlastender Verkürzung und Vermeiden einer gesteigerten Dura-(und Myelon-)deformierung erreicht werden kann. Letztendlich muss über das Ausmaß der max.…”

Spinal column shortening for tethered cord syndrome associated with myelomeningocele, lumbosacral lipoma, and lipomyelomeningocele in children and young adults

“…eThered cord syndrome is a clinical diagnosis with a constellation of signs and symptoms, including back and leg pain, other sensory changes, leg weakness, foot deformity, scoliosis, and bowel and bladder dysfunction. 9,22,23,26,27,30 The pathophysiology of tethered cord syndrome has been hypothesized to be an abnormal stretch of the spinal cord, leading to altered blood flow and hypoxic stress and subsequent worsened mitochondrial oxidative metabolism and electrophysiological insult. It is assumed that prolonged neuronal dysfunction may lead to structural damage to neuronal perikarya and axons.…”

“…33 Initial treatment for tethered cord syndrome may involve an untethering procedure, which consists of the surgical release of abnormal attachments between the neural elements, adjacent structures, and scar tissue, releasing excessive tension on the spinal cord. 20,30 While untethering is a well-accepted treatment option for tethered cord syndrome, 5,19,22 recurrent tethering from scar formation, a natural reaction to surgery, is a significant risk. Reported rates of secondary tethered cord syndrome following repair of myelomeningoceles have been estimated to be between 3% and 32%; the incidence of recurrent tethered cord syndrome after surgery for lipomyelomeningocele has been reported to be as high as 40%.…”

“…Reported rates of secondary tethered cord syndrome following repair of myelomeningoceles have been estimated to be between 3% and 32%; the incidence of recurrent tethered cord syndrome after surgery for lipomyelomeningocele has been reported to be as high as 40%. 30 Surgical untethering may lead to a vicious cycle of repeated untethering procedures during a patient's lifetime. With multiple untethering procedures, dense arachnoiditis encountered during dissection may increase the procedural risk of new neurological deficits from damage to the spinal cord and nerve roots.…”