Anatomic Position of a Herniated Nucleus Pulposus Predicts the Outcome of Lumbar Discectomy

Knop-Jergas, Barbara M.; Zucherman, James; Hsu, Ken Y.; DeLong, Bradford

doi:10.1097/00002517-199606000-00011

Cited by 54 publications

(27 citation statements)

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“…First, posterolateral herniations, a term used widely in in vitro studies, correspond to intra or extraforaminal herniations clinically [39][40][41]. Such herniations are far less common than central posterior or mediolateral posterior herniations [14,16,21].…”

Section: Discussionmentioning

confidence: 99%

The influence of torsion on disc herniation when combined with flexion

2010

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The role of torsion in the mechanical derangement of intervertebral discs remains largely undefined. The current study sought to investigate if torsion, when applied in combination with flexion, affects the internal failure mechanics of the disc wall when exposed to high nuclear pressure. Thirty ovine lumbar motion segments were each positioned in 2°axial rotation plus 7°fl exion. Whilst maintained in this posture, the nucleus of each segment was gradually injected with a viscous radioopaque gel, via an injection screw placed longitudinally within the inferior vertebra, until failure occurred. Segments were then inspected using micro-CT and optical microscopy in tandem. Five motion segments failed to pressurize correctly. Of the remaining 25 successfully tested motion segments, 17 suffered vertebral endplate rupture and 8 suffered disc failure. Disc failure occurred in mature motion segments significantly more often than immature segments. The most common mode of disc failure was a central posterior radial tear involving a systematic annulus-endplate-annulus failure pattern. The endplate portion of these radial tears often propagated contralateral to the direction of applied axial rotation, and, at the lateral margin, only those fibres inclined in the direction of the applied torque were affected. Apart from the 2°of applied axial rotation, the methods employed in this study replicated those used in a previously published study. Consequently, the different outcome obtained in this study can be directly attributed to the applied axial rotation. These inter-study differences show that when combined with flexion, torsion markedly reduces the nuclear pressure required to form clinically relevant radial tears that involve cartilaginous endplate failure. Conversely, torsion appears to increase the disc wall's resistance to radial tears that do not involve cartilaginous endplate failure, effectively halving the disc wall's overall risk of rupture.

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Section: Discussionmentioning

confidence: 99%

The influence of torsion on disc herniation when combined with flexion

2010

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“…In the cases of high canal compromised and high grade communicated migration types, assessment was via a posterolateral approach was used 26,27,30) . In the cases of a high grade non-communicated inferior sequestrated type, we accessed the pathology by an extreme lateral route 24) and suprapedicular approach 12) simultaneously. A 1 cm skin incision was made 8-12 cm from the midline according to the herniated disc type.…”

Section: Surgical Techniquementioning

confidence: 99%

Strategies for Noncontained Lumbar Disc Herniation by an Endoscopic Approach : Transforaminal Suprapedicular Approach, Semi-Rigid Flexible Curved Probe, and 3-Dimensional Reconstruction CT with Discogram

Chae

Lee

et al. 2009

J Korean Neurosurg Soc

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Objective : The purpose of this study was to evaluate the efficacy of a transforaminal suprapedicular approach, semi-rigid flexible curved probe, and 3-dimensional reconstruction computed tomography (3D-CT) with discogram in the endoscopic treatment of non-contained lumbar disc herniations. Methods : The subjects were 153 patients with difficult, non-contained lumbar disc herniations undergoing endoscopic treatment. The types of herniation were as follows : extraforaminal, 17 patients; foraminal, 21 patients; high grade migration, 59 patients; and high canal compromise, 56 patients. To overcome the difficulties in endoscopic treatment, the anatomic structures were analyzed by 3D reconstruction CT and the high grade disc was extracted using a semi-rigid flexible curved probe and a transforaminal suprapedicular approach. Results : The mean follow-up was 18.3 months. The mean visual analogue scale (VAS) of the patients prior to surgery was 9.48, and the mean postoperative VAS was 1.63. According to Macnab's criteria, 145 patients had excellent and good results, and thus satisfactory results were obtained in 94.77% cases. Conclusion : In a posterolateral endoscopic lumbar discectomy, the difficult, non-contained disc is considered to be the most important factor impeding the success of surgery. By applying a semi-rigid flexible curved probe and using a transforaminal suprapedicular approach, good surgical results can be obtained, even in high grade, non-contained disc herniations.

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“…The study has been criticized for selection bias, as the decision to treat operatively was not randomized. Knop-Jergas et al 6 studied the anatomic position of a lumbar disc herniation and its effect on clinical outcome of lumbar discectomy. Preoperative computed tomography scans and magnetic resonance imaging of the lumbar spine were taken and compared to those of patients and their respective outcomes from lumbar discectomy based on the SmileyÀWebster evaluation scale.…”

Section: Discussionmentioning

confidence: 99%