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Edward C Benzel

Publications and source records attributed to Edward C Benzel.

At least 19 recordsLinked to original sources
PubMed2005

Techniques for the ventral correction of postsurgical cervical kyphotic deformity.

Progressive kyphotic deformity of the cervical spine may be a late sequela of congenital cervical anomalies, degenerative disc disease, neoplasm, cervical trauma, and surgical procedures. Of these, postsurgical kyphosis is the most common and can occur after ventral and dorsal surgeries of the cervical spine. The purpose of this article is to review the causes and clinical presentation of postsurgical cervical kyphosis and to focus on the operative planning and ventral correction techniques.

Cervical Vertebrae↗
PubMed2005

Nonoperative management of vertical C2 body fractures.

OBJECTIVE: To estimate the incidence and to describe the clinical results of the nonoperative management of vertical C2 body fractures. METHODS: An 8-year retrospective review of upper cervical spine injuries from the registry of a level I trauma center identified 21 patients with a vertical C2 body fracture. RESULTS: Sixteen coronally oriented Type 1 vertical C2 body fractures and 5 sagittally oriented Type 2 vertical C2 body fractures were identified. These fractures account for approximately 10% of the upper cervical spine fractures identified over this period of time. One elderly patient with a Type 1 fracture died as a result of pneumonia, and two patients with Type 2 fractures died from severe closed-head injuries. One patient had evidence of spinal cord injury. This was not related to the C2 body fracture but rather to a subaxial cervical spine injury. Of the surviving 18 patients, all were managed nonoperatively (with external orthoses) and showed evidence of fusion (union of fracture fragments) at the time of the last follow-up. CONCLUSION: Vertical C2 body fractures are not rare injuries and can account for up to 10% of upper cervical spine injuries. In general, vertical C2 body fractures are amenable to nonoperative treatment with external orthoses.

Accidents, Traffic↗
PubMed2005

Effects of age on the perioperative characteristics and short-term outcome of posterior lumbar fusion surgery.

OBJECT: Although advances in patient care have enabled surgeons to perform posterior lumbar decompression and fusion (PLDF), increased age remains a major concern when designing a treatment strategy. The authors conducted a study to evaluate if increased age has any effect on lumbar fusion surgery in terms of perioperative events. METHODS: This retrospective study comprised 129 patients (age range 25-91 years) with spondylolisthesis, lumbar stenosis and/or disc degeneration/herniation with instability, or unsuccessful results after a failed previous PLDF. The patients were stratified by age: those younger than 65 years of age (85 patients) and those at least 65 years of age (44 patients). The parameters reviewed included comorbid conditions, American Society of Anesthesiologists score, instrumentation technique (pedicle screws, a combination of pedicle screw fixation [PSF] and posterior lumbar interbody fusion [PLIF], or noninstrumented fusions), number of fused levels, operative time, estimated blood loss (EBL), complications, and hospital length of stay (LOS). Fusion strategies in the elderly tended to be more conservative. Repeated operations and PSF/PLIF procedures were less frequent in the older age group. Older age did not result in increased complications, EBL, and operative time. Longer hospital LOS was observed in the older age group (7 +/- 3.5 days) compared with the younger age group (5.5 +/- 1.9 days) (p = 0.022). CONCLUSIONS: Complications and perioperative events following PLDF in the elderly are comparable with those observed in younger patients. Withholding lumbar spine fusion solely based on advanced age is not warranted.

Adult↗
PubMed2005

Stretch-associated injury in cervical spondylotic myelopathy: new concept and review.

The simple pathoanatomic concept that a narrowed spinal canal causes compression of the enclosed cord, leading to local tissue ischemia, injury, and neurological impairment, fails to explain the entire spectrum of clinical findings observed in cervical spondylotic myelopathy. A growing body of evidence indicates that spondylotic narrowing of the spinal canal and abnormal or excessive motion of the cervical spine results in increased strain and shear forces that cause localized axonal injury within the spinal cord. During normal motion, significant axial strains occur in the cervical spinal cord. At the cervicothoracic junction, where flexion is greatest, the spinal cord stretches 24% of its length. This causes local spinal cord strain. In the presence of pathological displacement, strain can exceed the material properties of the spinal cord and cause transient or permanent neurological injury. Stretch-associated injury is now widely accepted as the principal etiological factor of myelopathy in experimental models of neural injury, tethered cord syndrome, and diffuse axonal injury. Axonal injury reproducibly occurs at sites of maximal tensile loading in a well-defined sequence of intracellular events: myelin stretch injury, altered axolemmal permeability, calcium entry, cytoskeletal collapse, compaction of neurofilaments and microtubules, disruption of anterograde axonal transport, accumulation of organelles, axon retraction bulb formation, and secondary axotomy. Stretch and shear forces generated within the spinal cord seem to be important factors in the pathogenesis of cervical spondylotic myelopathy.

Biomechanical Phenomena↗
PubMed2004

Biomechanics of metastatic spine cancer.

The spine is the most common site of skeletal metastases. Most of these occur within the vertebral body, thereby predisposing patients to pathologic fracture. The risk of fracture is related to the extent of bony destruction, location of the lesion, and inherent bone quality. The regional variation in spine anatomy exposes the cervical,thoracic, and lumbar spines to different forces,resulting in varying fracture types.

Biomechanical Phenomena↗
PubMed2004

Outcome after the treatment of spinal dural arteriovenous fistulae: a contemporary single-institution series and meta-analysis.

OBJECTIVE: Spinal dural arteriovenous fistulae (Type I spinal AVMs) are the most common type of spinal vascular malformations. The optimal treatment strategy has yet to be defined, and endovascular embolization is being offered with increasing frequency. A 7-year single-institution retrospective review of outcome with surgical management of Type I spinal AVMs is presented along with a meta-analysis of existing literature. METHODS: For the institutional analysis, a retrospective review of all patients who underwent treatment at our institution for Type I spinal AVMs was performed. Between 1995 and the present (the time frame during which endovascular treatments were available), 19 consecutive patients were treated. Follow-up was performed by clinical examination or telephone interview, and functional status was measured by use of the Aminoff-Logue score. For the meta-analysis, a MEDLINE search between 1966 and the present was performed for surgical, endovascular, or combined treatment of spinal dural arteriovenous fistula. These series were included in a meta-analysis to evaluate success and failure rates, complications, and functional outcome. Specifically, embolization and microsurgery were compared. RESULTS: For the institutional analysis, 18 of 19 patients were available for long-term follow-up after surgery. There were no surgical failures, but one complication was seen. Patients demonstrated a statistically significant improvement in gait and bladder function after surgery. For the meta-analysis, 98% of those patients treated with microsurgery had their dural arteriovenous fistulae successfully obliterated after the initial treatment, compared with only 46% with embolization, as judged by radiographic or clinical follow-up. 89% percent of patients demonstrated improvement or stabilization in neurological symptoms after surgical treatment. Few complications were demonstrated with either surgery or embolization. CONCLUSION: At this point, surgery seems to be superior to embolization for the management of spinal dural arteriovenous fistula. The fistula is usually obliterated after the initial treatment, with few clinical or radiographic recurrences. The majority of patients either improve or stabilize after treatment. Few worsen, and the morbidity is minimal. It is reasonable to attempt initial embolization, especially at the time of the initial diagnostic spinal angiogram. The treating physicians and patients should be aware of the high chance of recurrence, and patients may ultimately require surgery or repeat embolization. After endovascular therapy, patients are committed to repeat angiography and probably embolization. For these reasons, it is the authors' opinion that surgery should be used as the first-line therapy for spinal dural arteriovenous fistulae.

Adult↗
PubMed2004

Prospective outcomes evaluation after decompression with or without instrumented fusion for lumbar stenosis and degenerative Grade I spondylolisthesis.

OBJECT: There is considerable debate among spine surgeons regarding whether fusion should be used to augment decompressive surgery in patients with symptomatic lumbar spinal stenosis involving Grade I degenerative spondylolisthesis. The authors prospectively evaluated the outcomes of patients treated between 2000 and 2002 at two institutions to determine whether fusion improves functional outcome 1 year after surgery. METHODS: Patients ranged in age from 50 to 81 years. They presented with degenerative Grade I (3- to 14-mm) spondylolisthesis and lumbar stenosis without gross instability (< 3 mm of motion at the level of subluxation). Those in whom previous surgery had been performed at the level of subluxation were excluded. Each patient completed Oswestry Disability Index (ODI) and Short Form-36 (SF-36) questionnaires preoperatively and at 6 to 12 months postoperatively. Some patients underwent decompression alone (20 cases), whereas others underwent decompression and posterolateral instrumentation-assisted fusion (14 cases), at the treating surgeon's discretion. Baseline demographic data, radiographic features, and ODI and SF-36 scores were similar in both groups. The 1-year fusion rate was 93%. Both forms of surgery independently improved outcome compared with baseline status, based on ODI and SF-36 physical component summary (PCS) results (p < 0.001). Decompression combined with fusion led to an improvement in ODI scores of 27.5 points, whereas decompression alone was associated with a 13.6-point increase (p = 0.02). Analysis of the SF-36 PCS data also demonstrated a significant intergroup difference (p = 0.003). CONCLUSIONS: Surgery substantially improved 1-year outcomes based on established outcomes instruments in patients with Grade I spondylolisthesis and stenosis. Fusion was associated with greater functional improvement.

Aged↗
PubMed2003

The biomechanics of iatrogenic spinal destabilization and implant failure.

Revision spinal surgery is usually indicated in cases of persistent or recurrent symptoms related to neural compression, spinal deformity, or construct failure. An understanding of fundamental biomechanical principles of both spinal decompression and reconstructive strategies is essential to avoid unnecessary subsequent spinal operations.

Biomechanical Phenomena↗
PubMed2003

A biomechanical comparison of facet screw fixation and pedicle screw fixation: effects of short-term and long-term repetitive cycling.

STUDY DESIGN: A biomechanical study was conducted to assess the stabilization performance of transfacet pedicle screw fixation. OBJECTIVE: To compare the biomechanical effects of short-term and long-term cyclic loading on lumbar motion segments instrumented with either a pedicle screw or a transfacet pedicle screw construct. SUMMARY OF BACKGROUND DATA: Facet screw fixation is an alternative to pedicle screw fixation that permits the use of a minimally invasive strategy. It is not known whether facet screw fixation can provide stability equivalent to pedicle screw fixation during cyclical loading. Therefore, transfacet pedicle screw fixation and standard pedicle screw fixation techniques were compared biomechanically. METHODS: Lumbar motion segments were tested under short-term and long-term cyclic loading conditions. For the short-term phase, specimens were tested intact for six cycles (to 400 N or 4 Nm) in compression, flexion, extension, lateral bending, and torsion. The specimens then were instrumented with bilateral semicircular interbody spacers and pedicle screw instrumentation or transfacet pedicle screws, and the testing sequence was repeated. For the long-term phase, 12 specimens were instrumented in a similar manner and loaded to 6 Nm of flexion bending for 180,000 cycles. RESULTS: For the short-term phase, both fixation systems had significantly greater stiffness and reduced range of motion, as compared with the intact state. No differences were observed between the fixation systems except in flexion, wherein transfacet pedicle screw specimens were significantly stiffer than traditional pedicle screw specimens. For the long-term phase, the stiffness and range of motion did not significantly increase or decrease over repetitive cycling of the instrumented specimens. Furthermore, no significant difference between the fixation systems was observed. CONCLUSIONS: The stability provided by both transfacet pedicle screw fixation and traditional pedicle screw fixation was not compromised after repetitive cycling. In this model, transfacet pedicle screw fixation appears equivalent biomechanically to traditional pedicle screw fixation.

Biocompatible Materials↗
PubMed2003

Biomechanics of spinal deformity.

The correction of spinal deformity may be achieved by a variety of methods, each of which has advantages and disadvantages. The goals of spinal deformity surgery include reasonable correction of the curvature, prevention of further deformation, improvement of sagittal and coronal balance, optimization of cosmetic issues, and restoration/preservation of function. The failure to consider all these factors appropriately may result in a suboptimal outcome. Understanding fundamental biomechanical principles involved in the formation, progression, and treatment of spinal deformities is essential in the clinical decision-making process.

Anthropometry↗
PubMed2003

Ventral correction of postsurgical cervical kyphosis.

OBJECT: Cervical kyphotic deformation may develop after surgery involving either the ventral or dorsal approach. Regardless of the cause, the development of a cervical kyphotic deformity should be avoided, if possible, and corrected if present, when appropriate. The authors describe their experience with a technique for the ventral correction of iatrogenic (postoperative) cervical kyphosis. METHODS: A retrospective review of cases involving correction of postoperative iatrogenic cervical kyphosis via an ventral approach was performed. The authors conducted an ventral approach to kyphosis correction. The procedure required specific head positioning (in extension), convergent distraction pins, and an ventrally placed implant (axially dynamic when appropriate) with multiple points of fixation including at least one point of intermediate fixation. The pre- and postoperative sagittal angle and clinical status were evaluated. During a nearly 14-month period, 12 patients met the inclusion criteria. Ten patients underwent a minimum of 6 months of follow up. They comprised the study population. Most patients presented with mechanical neck pain as part of their symptom profile. The mean magnitude of deformity correction (pre- to postoperative) was 20 degrees of lordosis. The mean postoperative sagittal angle was 6 degrees of lordosis. The mean change in the sagittal angle during the follow-up period was 2.2 degrees of lordosis. CONCLUSIONS: The ventral approach to correction of cervical deformity led to the achievement of lordosis in all but one patient. This posture was effectively maintained during the follow-up period. All patients exhibited improvement postoperatively; three experienced complete resolution of their preoperative symptoms. When symptoms are related to postsurgical kyphosis, deformity correction should be considered. Such a procedure may be performed effectively via an ventral approach in most circumstances.

Adolescent↗