A biomechanical comparison of three surgical approaches in bilateral subaxial cervical facet dislocation

2004 ◽  
Vol 1 (1) ◽  
pp. 108-115 ◽  
Author(s):  
Sung-Min Kim ◽  
T. Jesse Lim ◽  
Josemaria Paterno ◽  
Jon Park ◽  
Daniel H. Kim
Keyword(s):  
Statistical Significance ◽  
Axial Rotation ◽  
Anterior Cervical Discectomy ◽  
Content Type ◽  
Facet Dislocation ◽  
Loading Modes ◽  
Cervical Facet ◽  
Effective Stabilization ◽  
Flexion And Extension ◽  
Fine Print

Object. In bilateral cervical facet dislocation, biomechanical stabilities between anterior locking screw/plate fixation after anterior cervical discectomy and fusion (ACDFP) and posterior transpedicular screw/rod fixation after anterior cervical discectomy and fusion (ACDFTP) have not been compared using the human cadaver, although ACDFP has been performed frequently. In this study the stability of ACDFP, a posterior wiring procedure after ACDFP (ACDFPW), and ACDFTP for treatment of bilateral cervical facet dislocation were compared. Methods. Spines (C3—T1) from 10 human cadavers were tested in the intact state, and then after ACDFP, ACDFPW, and ACDFTP were performed. Intervertebral motion was measured using a video-based motion capture system. The range of motion (ROM) and neutral zone (NZ) were compared for each loading mode to a maximum of 2 Nm. The ROM for spines treated with ACDFP was below that of the intact spine in all loading modes, with statistical significance in flexion and extension, but NZs were decreased in flexion and extension and slightly increased in bending and axial rotation; none of these showed statistical significance. The ACDFPW produced statistically significant additional stability in axial rotation ROM and in flexion NZ than ACDFP. The ACDFTP provided better stability than ACDFP in bending and axial rotation, and better stability than ACDFPW in bending for both ROM and NZ. There was no significant difference in extension with either ROM or NZ for the three fixation methods. Conclusions. The spines treated with ACDFTP demonstrated the most effective stabilization, followed by those treated with ACDFPW, and then ACDFP. The spines receiving ACDFP also revealed a higher stability than the intact spine in most loading modes; thus ACDFP can also provide a relatively effective stabilization in bilateral cervical facet dislocation, but with the aid of a brace.

Craniovertebral junction fixation with transarticular screws: biomechanical analysis of a novel technique

2003 ◽  
Vol 98 (2) ◽  
pp. 202-209 ◽  
Author(s):  
L. Fernando Gonzalez ◽  
Neil R. Crawford ◽  
Robert H. Chamberlain ◽  
Luis E. Perez Garza ◽  
Mark C. Preul ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Axial Rotation ◽  
Craniovertebral Junction ◽  
Biomechanical Analysis ◽  
Lateral Bending ◽  
Content Type ◽  
Additional Stability ◽  
A New Technique ◽  
Flexion And Extension ◽  
Fine Print

Object. The authors compared the biomechanical stability resulting from the use of a new technique for occipitoatlantal motion segment fixation with an established method and assessed the additional stability provided by combining the two techniques. Methods. Specimens were loaded using nonconstraining pure moments while recording the three-dimensional angular movement at occiput (Oc)—C1 and C1–2. Specimens were tested intact and after destabilization and fixation as follows: 1) Oc—C1 transarticular screws plus C1–2 transarticular screws; 2) occipitocervical transarticular (OCTA) plate in which C1–2 transarticular screws attach to a loop from Oc to C-2; and (3) OCTA plate plus Oc—C1 transarticular screws. Occipitoatlantal transarticular screws reduced motion to well within the normal range. The OCTA loop and transarticular screws allowed a very small neutral zone, elastic zone, and range of motion during lateral bending and axial rotation. The transarticular screws, however, were less effective than the OCTA loop in resisting flexion and extension. Conclusions. Biomechanically, Oc—C1 transarticular screws performed well enough to be considered as an alternative for Oc—C1 fixation, especially when instability at C1–2 is minimal. Techniques for augmenting these screws posteriorly by using a wired bone graft buttress, as is currently undertaken with C1–2 transarticular screws, may be needed for optimal performance.

Cervical facet dislocation: techniques for ventral reduction and stabilization

2000 ◽  
Vol 92 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Bernardo J. Ordonez ◽  
Edward C. Benzel ◽  
Sait Naderi ◽  
Simcha J. Weller
Keyword(s):  
Cervical Spine ◽  
Surgical Approach ◽  
Plate Fixation ◽  
Neurological Status ◽  
Content Type ◽  
Facet Dislocation ◽  
Cord Injury ◽  
Complete Spinal Cord Injury ◽  
Cervical Facet ◽  
Fine Print

Object. To demonstrate the safety and utility of one surgical approach, the authors reviewed their experience with the ventral surgical approach for decompression, reduction, and stabilization in 10 patients with either unilateral or bilateral cervical facet dislocation. Methods. Six patients presented with unilateral cervical facet dislocation and four patients with bilateral cervical facet dislocation. There were six male and four female patients who ranged in age from 17 to 72 years (average 37.1 years). The level of facet dislocation was C4–5 in one, C5–6 in four, and C6–7 in five patients. Three patients presented with a complete spinal cord injury (SCI), three patients with an incomplete SCI, three with radicular symptoms or myeloradiculopathy, and one patient was neurologically intact. All patients underwent plain radiography, magnetic resonance imaging, and computerized tomography evaluation of the cervical spine. All patients had sustained significant ligamentous injury with minimum or no bone disruption. All patients underwent ventral decompressive surgery, reduction of the dislocation, and stabilization of the cervical spine. Techniques for performing ventral reduction of unilateral or bilateral cervical facet dislocation are described. Decompression, reduction, and stabilization of the cervical spine via the ventral approach was accomplished in all but one patient. This patient underwent a ventral decompressive procedure and an attempt at ventral reduction and subsequent dorsal reduction and fusion in which a lateral mass screw plate fixation system was used; this was followed by ventral placement of instrumentation and fusion. There were no surgery-related complications. Postoperative neurological status was unchanged in four patients and improved in six patients. No patient experienced neurological deterioration after undergoing this surgical approach. Conclusions. The authors conclude that a ventral surgical decompression, reduction, and stabilization procedure provides a safe and effective alternative for the treatment of patients with unilateral or bilateral cervical facet dislocation without significant bone disruption.

Anterior cervical arthrodesis using DOC dynamic stabilization implant for improvement in sagittal angulation and controlled settling

2003 ◽  
Vol 98 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Bikash Bose
Keyword(s):  
Anterior Cervical Discectomy ◽  
Related Complication ◽  
Common Procedure ◽  
Content Type ◽  
Cervical Discectomy ◽  
Arm Pain ◽  
Advantages And Disadvantages ◽  
Cervical Spondylotic Radiculopathy ◽  
Donor Graft ◽  
Fine Print

Object. Placing instrumentation in the anterior cervical spine is a common procedure. The bi- and unicortical systems currently available, however, have distinct advantages and disadvantages. The author reports a prospective series in which a new dynamized anterior cervical fixation system was evaluated. Methods. Thirty-seven patients underwent anterior cervical discectomy and fusion in which the DOC ventral cervical stabilization system was used for indications including cervical spondylotic radiculopathy, disc herniation, trauma, and myelopathy. Patients underwent anterior cervical discectomy and interbody fusion and/or corpectomy. Preoperative and postoperative clinical data included assessment of spinal cord and nerve root deficit, function, neck pain, and arm pain. Preoperative and postoperative radiographic data included sagittal angle, translation, and settling of the graft. Fusion status was determined by the presence of trabecular bridging bone on plain anteroposterior and lateral cervical radiographs. At a mean follow-up time of 1.3 years, postoperative neck or arm pain was resolved in 52% of the patients, restriction on function was mild or absent in 88%, and fusion was successful in 80% of patients and 88% of the treated levels. There was one implant-related complication, one significant dysphagia complication, and a 10.8% donor graft site complication rate. Conclusions. The use of this system led to a high percentage of pain relief and radiographic fusion. The sagittal angle was controlled while allowing for graft settling. There were no implant failures.

Traumatic subarachnoid hemorrhage on the computerized tomography scan obtained at admission: a multicenter assessment of the accuracy of diagnosis and the potential impact on patient outcome

2003 ◽  
Vol 98 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Cristina Mattioli ◽  
Luigi Beretta ◽  
Simonetta Gerevini ◽  
Fabrizio Veglia ◽  
Giuseppe Citerio ◽  
...  
Keyword(s):  
Patient Outcome ◽  
Subarachnoid Hemorrhage ◽  
Computerized Tomography ◽  
Statistical Significance ◽  
Unfavorable Outcome ◽  
Content Type ◽  
Ct Findings ◽  
Traumatic Subarachnoid Hemorrhage ◽  
Injured Patients ◽  
Fine Print

Object. The goal of this study was fourfold: 1) to determine the incidence of traumatic subarachnoid hemorrhage (tSAH) in patients with traumatic brain injury (TBI); 2) to verify agreement in the diagnosis of tSAH in a multicenter study; 3) to assess the incidence of tSAH on the outcome of the patient; and 4) to establish whether tSAH itself leads to an unfavorable outcome or whether it is a sign of major brain trauma associated with severe posttraumatic lesions. Methods. Computerized tomography (CT) scans obtained in 169 head-injured patients on admission to 12 Italian intensive care units during a 3-month period were examined. The scans were collected for neuroradiological review and were used for the analysis together with data from a multicenter database (Neurolink). A review committee found a high incidence of tSAH (61%) in patients with TBI and a moderate agreement among centers (K = 0.57). Significant associations were observed between the presence and grading of tSAH and patient outcomes, and between the presence of tSAH and the severity of the CT findings. Logistic regression analysis showed that the presence of tSAH and its grading alone do not assume statistical significance in the prediction of unfavorable outcome. Conclusions. Traumatic SAH frequently occurs in patients with TBI, but it is difficult to detect and grade. Traumatic SAH is associated with more severe CT findings and a worse patient outcome.

Stabilizing effect of posterior lumbar interbody fusion cages before and after cyclic loading

2000 ◽  
Vol 92 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Annette Kettler ◽  
Hans-Joachim Wilke ◽  
Rupert Dietl ◽  
Matthias Krammer ◽  
Christianto Lumenta ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Interbody Fusion ◽  
Posterior Lumbar Interbody Fusion ◽  
Axial Rotation ◽  
Lumbar Interbody Fusion ◽  
Lateral Bending ◽  
Content Type ◽  
Flexion Extension ◽  
Stabilizing Effect ◽  
Fine Print

Object. The function of interbody fusion cages is to stabilize spinal segments primarily by distracting them as well as by allowing bone ingrowth and fusion. An important condition for efficient formation of bone tissue is achieving adequate spinal stability. However, the initial stability may be reduced due to repeated movements of the spine during everyday activity. Therefore, in addition to immediate stability, stability after cyclic loading is of remarkable relevance; however, this has not yet been investigated. The object of this study was to investigate the immediate stabilizing effect of three different posterior lumbar interbody fusion cages and to clarify the effect of cyclic loading on the stabilization. Methods. Before and directly after implantation of a Zientek, Stryker, or Ray posterior lumbar interbody fusion cage, 24 lumbar spine segment specimens were each evaluated in a spine tester. Pure lateral bending, flexion—extension, and axial rotation moments (± 7.5 Nm) were applied continuously. The motion in each specimen was measured simultaneously. The specimens were then loaded cyclically (40,000 cycles, 5 Hz) with an axial compression force ranging from 200 to 1000 N. Finally, they were tested once again in the spine tester. Conclusions. In general, a decrease of movement in all loading directions was noted after insertion of the Zientek and Ray cages and an increase of movement after implantation of a Stryker cage. In all three cage groups greater stability was demonstrated in lateral bending and flexion than in extension and axial rotation. Reduced stability during cyclic loading was observed in all three cage groups; however, loss of stability was most pronounced when the Ray cage was used.

Unilateral facetectomy approach for lateral lumbar disc herniation

1991 ◽  
Vol 74 (5) ◽  
pp. 754-756 ◽  
Author(s):  
Eddy Garrido ◽  
P. Noel Connaughton
Keyword(s):  
Disc Herniation ◽  
Lumbar Fusion ◽  
Lumbar Disc ◽  
Herniated Disc ◽  
Spinal Instability ◽  
Content Type ◽  
X Ray ◽  
Flexion And Extension ◽  
Fine Print

✓ Forty-one patients with herniated lumbar discs in a lateral location underwent unilateral complete facetectomy for removal of their disc herniation. The diagnosis was made by computerized tomography in all patients. The follow-up period varied between 4 and 60 months, with an average of 22.4 months. All patients underwent dynamic lumbar spine x-ray films with flexion and extension exposures at various times during their follow-up period. The results were excellent in 35 patients, good in three, and poor in three. One patient suffered spinal instability postoperatively and required lumbar fusion because of back pain. Unilateral facetectomy gives an excellent view of the affected nerve root and the herniated disc, and the risk of spinal instability is very low.

Normal changes in orbital volume during childhood

2002 ◽  
Vol 96 (4) ◽  
pp. 742-746 ◽  
Author(s):  
Robert P. Bentley ◽  
Spyros Sgouros ◽  
Kalyan Natarajan ◽  
M. Stephen Dover ◽  
Anthony D. Hockley
Keyword(s):  
Statistical Significance ◽  
Significant Proportion ◽  
Magnetic Resonance Images ◽  
Healthy Children ◽  
Content Type ◽  
Linear Pattern ◽  
Orbital Volume ◽  
Disease States ◽  
The Difference ◽  
Fine Print

Object. The aim of this study was to construct a model of changes in orbital volume that occur throughout childhood from the age of 1 month to 15 years, which could be used for comparative studies of disease states affecting orbital growth. Methods. Using the procedure of segmentation on magnetic resonance images obtained in 67 healthy children, orbital volume was measured and plotted against age. During the first few months of life left orbital volume is on average 15 cm3 in male and 13 cm3 in female infants; these volumes increase to 26 cm3 and 24 cm3, respectively, by the time the child reaches 15 years of age. During the first few months of life right orbital volume is on average 16 cm3 in male and 13 cm3 in female infants; these volumes increase to 27 cm3 and 25 cm3, respectively, by the time the child is 15 years old. This represents an overall increase in orbital volume by a factor of 1.7 in boys and 1.8 in girls. By the time the child has reached 5 years of age, the orbital volume for both right and left sides has reached on average 77% of the volume seen at 15 years in both sexes. The differences between the two sides are not statistically significant for either sex. The change in orbital volume that is associated with age in general displays a linear pattern. Throughout childhood, orbital volumes are larger in boys than in girls, but share a similar growth pattern. The difference between the two sexes tends toward statistical significance during the first 5 years of life (left orbit p = 0.1, right orbit p = 0.04). Conclusions. During early childhood, orbital volume increases in a linear fashion, achieving a significant proportion of its final growth by the time the child is 5 years old.

Stability of the craniovertebral junction after unilateral occipital condyle resection: a biomechanical study

1999 ◽  
Vol 90 (1) ◽  
pp. 91-98 ◽  
Author(s):  
A. Giancarlo Vishteh ◽  
Neil R. Crawford ◽  
M. Stephen Melton ◽  
Robert F. Spetzler ◽  
Volker K. H. Sonntag ◽  
...  
Keyword(s):  
Axial Rotation ◽  
Craniovertebral Junction ◽  
Biomechanical Study ◽  
Occipital Condyle ◽  
Upper Cervical Spine ◽  
Lateral Bending ◽  
Content Type ◽  
Axial Translation ◽  
Flexion Extension ◽  
Fine Print

Object. The authors sought to determine the biomechanics of the occipitoatlantal (occiput [Oc]—C1) and atlantoaxial (C1–2) motion segments after unilateral gradient condylectomy. Methods. Six human cadaveric specimens (skull with attached upper cervical spine) underwent nondestructive biomechanical testing (physiological loads) during flexion—extension, lateral bending, and axial rotation. Axial translation from tension to compression was also studied across Oc—C2. Each specimen served as its own control and underwent baseline testing in the intact state. The specimens were then tested after progressive unilateral condylectomy (25% resection until completion), which was performed using frameless stereotactic guidance. At Oc—C1 for all motions that were tested, mobility increased significantly compared to baseline after a 50% condylectomy. Flexion—extension, lateral bending, and axial rotation increased 15.3%, 40.8%, and 28.1%, respectively. At C1–2, hypermobility during flexion—extension occurred after a 25% condylectomy, during axial rotation after 75% condylectomy, and during lateral bending after a 100% condylectomy. Conclusions. Resection of 50% or more of the occipital condyle produces statistically significant hypermobility at Oc—C1. After a 75% resection, the biomechanics of the Oc—C1 and C1–2 motion segments change considerably. Performing fusion of the craniovertebral junction should therefore be considered if half or more of one occipital condyle is resected.

Significance of proliferating cell nuclear antigen in predicting recurrence of intracranial meningioma

1996 ◽  
Vol 84 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Mark A. Cobb ◽  
Muhammad Husain ◽  
Bruce J. Andersen ◽  
Ossama Al-Mefty
Keyword(s):  
Proliferating Cell Nuclear Antigen ◽  
Statistical Significance ◽  
Tumor Biology ◽  
Nuclear Antigen ◽  
Intracranial Meningioma ◽  
Content Type ◽  
Tumor Histology ◽  
Proliferating Cell ◽  
Fine Print

✓ It is well known that the histological appearance of meningiomas often fails to predict accurately the clinical behavior of the tumor. Therefore, attention has turned from tumor histology to tumor biology. Proliferating cell nuclear antigen (PCNA), a cell cycle-regulated protein, has been recently characterized as the cofactor of DNA polymerase-δ, an enzyme required for DNA replication. The rate of synthesis of PCNA directly correlates with the proliferative state of cells. Immunohistochemical labeling of this antigen is now possible with monoclonal antibodies that allow for its demonstration in routinely fixed, paraffin-embedded specimens. In this study, the PCNA labeling index (LI) was determined for 83 meningiomas, including tumors with both benign and malignant clinical courses and with benign, atypical, and malignant histologies, apparent after total or subtotal resections. No statistical difference was found between the LI on recurrence and that found at initial presentation. In addition, stepwise multivariate regression analysis failed to identify any combination of factors (age, gender, race, age of specimen, tumor histology, Simpson grade of resection) that contributes to the predictive strength of the PCNA LI for tumor recurrence. However, for LIs less than 2%, only one of 26 gross totally resected tumors recurred (mean follow up 53 months); for LIs more than 7%, five of 13 gross totally resected tumors recurred (mean follow up 55 months). The difference in recurrence rates between gross totally resected meningiomas with PCNA LIs less than 2% and those with PCNA LIs more than 7% achieved statistical significance with a Fisher's exact probability equaling 0.011. The authors conclude that quantitative PCNA labeling of meningiomas is a promising technique that can provide meaningful prognostic information.

Bilateral vocal cord paralysis following anterior cervical discectomy and fusion

1998 ◽  
Vol 89 (5) ◽  
pp. 839-843 ◽  
Author(s):  
Thomas J. Manski ◽  
Michael D. Wood ◽  
Stewart B. Dunsker
Keyword(s):  
Vocal Cord ◽  
Surgical Procedure ◽  
Vocal Cord Paralysis ◽  
Anterior Cervical Discectomy ◽  
Neurosurgical Procedures ◽  
Bilateral Vocal Cord Paralysis ◽  
Content Type ◽  
Cervical Discectomy ◽  
Unilateral Vocal Cord Paralysis ◽  
Fine Print

✓ The authors report a rare case of bilateral vocal cord paralysis following anterior cervical discectomy and fusion (ACD/F) in a patient who had a preexisting, clinically silent, and unrecognized unilateral vocal cord paralysis from a remote cardiac surgical procedure. The patient, a 41-year-old woman who developed acute respiratory stridor and respiratory insufficiency at the time of extubation after undergoing a C6–7 ACD/F, required emergency reintubation and ventilation. Otolaryngological evaluation revealed bilateral vocal cord paralysis with one vocal cord showing evidence of acute paralysis and the other showing evidence of chronic paralysis. She eventually required a permanent tracheotomy. The patient had undergone previous cardiac surgical procedures to correct Fallot's tetralogy as a neonate and as a child. At those times, there were no recognized symptoms of transient or permanent vocal cord dysfunction. This case emphasizes the importance of identifying patients with preexisting unilateral vocal cord paralysis before performing neurosurgical procedures such as ACD/F, which can place the only functioning vocal cord at risk for paralysis. Guidelines for identifying patients with preexisting unilateral vocal cord paralysis and for modifying the surgical procedure for ACD/F to prevent the catastrophic complication of bilateral vocal cord paralysis are discussed.

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