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Biomedical subjects

Christopher I Shaffrey

Publications and source records attributed to Christopher I Shaffrey.

17 recordsLinked to original sources
PubMed2007

Dorsal surgery for myelopathy and myeloradiculopathy.

OBJECTIVE: To review the dorsal approaches to the cervical spine for myelopathy and myeloradiculopathy. METHODS: The literature was reviewed in reference to dorsal approaches for cervical myelopathy and myeloradiculopathy. RESULTS: There are a variety of surgical approaches in the management of cervical myelopathy and myeloradiculopathy. Deciding which is the best method for any individual requires the surgeon to be aware of the advantages of each technique, as well as the complications and limitations of each approach. CONCLUSION: Laminectomy is the traditional technique used for multilevel cervical stenosis. The complications related to laminectomy, such as late neurological decline, kyphosis, instability, and postoperative radiculopathy, led to laminectomy with fusion. In Japan, dissatisfaction with both laminectomy and laminectomy with fusion led to the development of laminoplasty for dorsal treatment of multilevel cervical stenosis. This article highlights the salient features of preoperative evaluation in this patient population as it pertains to dorsal surgical approaches. Additionally, the techniques of laminectomy, laminectomy with fusion, and laminoplasty are compared, and the results are reviewed.

Humans↗
PubMed2006

Cervical spine injuries in pediatric athletes: mechanisms and management.

Sports-related injuries to the spine, although relatively rare compared with head injuries, contribute to significant morbidity and mortality in children. The reported incidence of traumatic cervical spine injury in pediatric athletes varies, and most studies are limited because of the low prevalence of injury. The anatomical and biomechanical differences between the immature spine of pediatric patients and the mature spine of adults that make pediatric patients more susceptible to injury include a greater mobility of the spine due to ligamentous laxity, shallow angulations of facet joints, immature development of neck musculature, and incomplete ossification of the vertebrae. As a result of these differences, 60 to 80% of all pediatric vertebral injuries occur in the cervical region. Understanding pediatric injury biomechanics in the cervical spine is important to the neurosurgeon, because coaches, parents, and athletes who place themselves in positions known to be associated with spinal cord injury (SCI) run a higher risk of such injury and paralysis. The mechanisms of SCI can be broadly subclassified into five types: axial loading, dislocation, lateral bending, rotation, and hyperflexion/hyperextension, although severe injuries often result from a combination of more than one of these subtypes. The aim of this review was to detail the characteristics and management of pediatric cervical spine injury.

Athletic Injuries↗
PubMed2006

Complications in spinal fusion for adolescent idiopathic scoliosis in the new millennium. A report of the Scoliosis Research Society Morbidity and Mortality Committee.

STUDY DESIGN: The Morbidity and Mortality database of the Scoliosis Research Society (SRS) was queried as to the incidence and type of complications as reported by its members for the treatment of adolescent idiopathic scoliosis (AIS) with spinal fusion and instrumentation procedures regarding surgical approach (anterior, posterior, or combined anterior-posterior) during a recent 3-year period. OBJECTIVE: To evaluate the incidence of surgeon-reported complications in a large series of spinal fusions with instrumentation for a single spinal deformity diagnosis and age group regarding surgical approach. SUMMARY OF BACKGROUND DATA: The SRS has been collecting morbidity and mortality data from its members since its formation in 1965 with the intent of using these data to assess the complications and adverse outcomes (death and/or spinal cord injury) of surgical treatment for spinal deformity. Surgical approaches to the management of treatment of AIS have a measurable impact on efficacy of correction, levels fused, and operative morbidity. However, there is a lack of consensus on the choice of surgical approach for the treatment of spinal deformity. METHODS: Of the 58,197 surgical cases submitted by members of the SRS in the years 2001, 2002, and 2003, 10.9% were identified as having had anterior, posterior, or combined spinal fusion with instrumentation for the diagnosis of AIS, and comprised the study cohort. All reported complications were tabulated and totaled for each of the 3 types of procedures, and statistical analysis was conducted. RESULTS: Complications were reported in 5.7% of the 6334 patients in this series. Of the 1164 patients who underwent anterior fusion and instrumentation, 5.2% had complications, of the 4369 who underwent posterior instrumentation and fusion, 5.1% had complications, and of the 801 who underwent combined instrumentation and fusion, 10.2% had complications. There were 2 patients (0.03%) who died of their complications. There was no statistical difference in overall complication rates between anterior and posterior procedures. However, the difference in complication rates between anterior or posterior procedures compared to combined procedures was highly significant (P < 0.0001). The differences in neurologic complication rates between combined and anterior procedures, as well as combined and posterior procedures were also highly statistically significant (P < 0.0001), but not between anterior and posterior procedures. CONCLUSIONS: This study shows that complication rates are similar for anterior versus posterior approaches to AIS deformity correction. Combined anterior and posterior instrumentation and fusion has double the complication rate of either anterior or posterior instrumentation and fusion alone. Combined anterior and posterior instrumentation and fusion also has a significantly higher rate of neurologic complications than anterior or posterior instrumentation and fusion alone.

Adolescent↗
PubMed2006

Degenerative lumbar scoliosis.

In adults, symptomatic scoliosis is usually a de novo primary degenerative deformity that develops in the fifth or sixth decade or an unrecognized or untreated idiopathic deformity with superimposed degeneration. The evaluation and treatment of adult scoliosis must focus on addressing patient symptoms while limiting the consequences of the treatment. The presence of neurological deficits, the flexibility of the deformity, the coronal and sagittal balance, and status of spinal segments outside of the main deformity are all important considerations when planning surgery. The complication rate of deformity surgery in adults is potentially high; but excellent functional outcome and patient satisfaction can occur with thorough preoperative patient education and meticulous surgical technique.

Adult↗
PubMed2006

Intrarater and interrater reliability and validity in the assessment of the mechanism of injury and integrity of the posterior ligamentous complex: a novel injury severity scoring system for thoracolumbar injuries. Invited submission from the Joint Section Meeting On Disorders of the Spine and Peripheral Nerves, March 2005.

OBJECT: A new classification and treatment algorithm for thoracolumbar injuries was recently introduced by Vaccaro and colleagues in 2005. A thoracolumbar injury severity scale (TLISS) was proposed for grading and guiding treatment for these injuries. The scale is based on the following: 1) the mechanism of injury; 2) the integrity of the posterior ligamentous complex (PLC); and 3) the patient's neurological status. The reliability and validity of assessing injury mechanism and the integrity of the PLC was assessed. METHODS: Forty-eight spine surgeons, consisting of neurosurgeons and orthopedic surgeons, reviewed 56 clinical thoracolumbar injury case histories. Each was classified and scored to determine treatment recommendations according to a novel classification system. After 3 months the case histories were reordered and the physicians repeated the exercise. Validity of this classification was good among reviewers; the vast majority (> 90%) agreed with the system's treatment recommendations. Surgeons were unclear as to a cogent description of PLC disruption and fracture mechanism. CONCLUSIONS: The TLISS demonstrated acceptable reliability in terms of intra- and interobserver agreement on the algorithm's treatment recommendations. Replacing injury mechanism with a description of injury morphology and better definition of PLC injury will improve inter- and intraobserver reliability of this injury classification system.

Algorithms↗
PubMed2006

Anterior stabilization of three-column thoracolumbar spinal trauma.

OBJECT: The purpose of this study was to evaluate the results obtained in patients who underwent anterior stabilization for three-column thoracolumbar fractures. METHODS: The authors retrospectively reviewed available clinical and radiographic data (1997-2006) to classify three-column thoracolumbar fractures according to the Association for the Study of Internal Fixation (AO) system, neurological status, spinal canal compromise, pre- and postoperative segmental angulation, and arthrodesis rate. The mean computed tomography-measured preoperative spinal canal compromise was 48.3% (range 8-92%), and the mean vertebral body height loss was 39.4%. The mean preoperative kyphotic deformity of 14.9 degrees improved to 4.6 degrees at the final follow-up examination. Although this angulation had increased a mean of 1.8 degrees during the follow-up period, the extent of correction was still significant compared with the preoperative angulation (p < 0.01). There were no cases of vascular complication or neurological deterioration. CONCLUSIONS: Contemporary anterior spinal reconstruction techniques can allow certain types of unstable three-column thoracolumbar fractures to be treated via an anterior approach alone. Compared with traditional posterior approaches, the anterior route spares lumbar motion segments and obviates the need for harvesting of the iliac crest.

Adolescent↗
PubMed2005

Thoracolumbar vertebral reconstruction after surgery for metastatic spinal tumors: long-term outcomes.

OBJECT: Metastatic spinal tumors continue to represent a major problem for patients and treating physicians. The purpose of this study was to assess quantitatively the functional outcome, quality of life, and survival rates of patients after major reconstructive spine surgery. METHODS: A prospective database was established and 58 patients were identified who had undergone thoracolumbar vertebral reconstruction for metastatic spinal tumors between March 1993 and October 1999. Surgical indications included disabling pain (92%) and/or progressive neurological dysfunction (60%). Forty-nine patients (85%) had clinical improvement in pain as determined based on the Oswestry pain scale (p < 0.05); 60% demonstrated improvement in their neurological status. The mean neurological improvement in Frankel grade was 1.2 (p < 0.05). The 12-month survival rate was 65%, and all patients who were ambulatory after surgery remained so until the time of death. Instrumentation failure requiring repeated operation occurred in two patients (3.5%), and in 12 patients (21%) local tumor recurrence necessitated repeated surgery. There were no cases of neurological deficit or death related to surgery. CONCLUSIONS: Major anterior thoracolumbar vertebral reconstruction is an effective treatment for local tumor control. More importantly, the authors have demonstrated that surgical treatment can significantly improve the quality of life by improvement of pain control and maintenance of ambulation during the patient's remaining life span.

Humans↗
PubMed2004

The future of spinal arthroplasty: a biomaterial perspective.

Both total hip and knee arthroplasty have demonstrated outstanding clinical results. The functional spinal unit composed of the intervertebral disc and facet joints is at least as complex. The intricacies of the coupled motions of the functional spinal unit have made development of an artificial disc a challenge. There have been several failed attempts to create a disc replacement that recapitulates normal motion while providing significant longevity and a low incidence of complications. Better understanding of the biomechanics of the intervertebral disc complex and improvements in implant material have made successful intervertebral disc replacement a likely reality, now that several artificial discs have completed Food and Drug Administration clinical trials. In this manuscript the authors detail the biomaterials used in disc arthroplasty and discuss joint wear and the host response to wear debris.

Arthroplasty↗
PubMed2004

Similarities and differences in the treatment of spine trauma between surgical specialties and location of practice.

STUDY DESIGN: Questionnaires administered to practicing orthopedic and neurosurgical spine surgeons from various regions of the United States and abroad. OBJECTIVES: To determine similarities and differences in the treatment of spinal trauma. SUMMARY OF BACKGROUND DATA: Spinal trauma is generally referred to subspecialists of orthopedic or neurosurgical training. Prior studies have suggested that there is significant variability in the management of such injuries. METHODS: Questionnaires based on eight clinical scenarios of commonly encountered cervical, thoracic, and lumbar injuries were administered to 35 experienced spinal surgeons. Surgeons completed profile information and answered approximately one dozen questions for each case. Data were analyzed with SPSS software to determine the levels of agreement and characteristics of respondents that might account for a lack of agreement on particular aspects of management. RESULTS: Of the 35 surgeons completing the questionnaire, 63% were orthopedists, 37% were neurosurgeons, and 80% had been in practice for more than 5 years. Considerable agreement was found in the majority of clinical decisions, including whether or not to operate and the timing of surgery. Of the differences noted, neurosurgeons were more likely to obtain a MRI, and orthopedists were more likely to use autograft as a sole graft material. Physicians from abroad were, in general, more likely to operate and to use an anterior approach during surgery than physicians from the northeastern United States. CONCLUSIONS: More commonalities were identified in the management of spinal trauma than previously reported. When found, variability in opinion was related to professional and regional differences.

Adult↗
PubMed2004

Aneurysmal bone cyst of the atlas: successful treatment through selective arterial embolization: case report.

OBJECTIVE AND IMPORTANCE: Aneurysmal bone cysts (ABCs) are benign and expansile osteolytic lesions that can occur in any location in the spine, including the craniovertebral junction. Aggressive resection followed by bone grafting has been the mainstay of treatment, with selective arterial embolization as a presurgical adjunct. Complete excision of these lesions at the craniovertebral junction is associated with high surgical morbidity. We report a case of successful treatment of an ABC of the atlas in a child with selective arterial embolization alone. CLINICAL PRESENTATION: A 10-year-old girl presented with persistent neck pain after a snowboarding accident. Computed tomography and magnetic resonance imaging of the cervical spine revealed an expansile cystic mass involving the right lateral mass of C1. Digital subtraction angiography revealed a tumor blush, which, along with the cystic appearance of the lesion, was consistent with an ABC. INTERVENTION: The arterial feeders to the lesion were selectively embolized with polyvinyl alcohol particles. Three sessions of embolization were required to eradicate the blood supply to the lesion completely. CONCLUSION: Complete surgical resection of ABCs at the craniovertebral junction can be associated with high morbidity secondary to the highly vascular and destructive nature of these lesions. The case discussed here demonstrates the viability of selective arterial embolization as a primary and stand-alone modality of treatment.

Bone Cysts, Aneurysmal↗
PubMed2003

Management of iatrogenic flat-back syndrome.

Iatrogenic loss of lordosis is now frequently recognized as a complication following placement of thoracolumbar instrumentation, especially with distraction instrumentation. Flat-back syndrome is characterized by forward inclination of the trunk, inability to stand upright, and back pain. Evaluation of the deformity should include a full-length lateral radiograph obtained with the patient's knees and hips fully extended. The most common cause of the deformity includes the use of distraction instrumentation in the lumbar spine and pseudarthrosis. Surgical treatment described in the literature includes opening (Smith-Petersen) osteotomy, polysegmental osteotomy, and closing wedge osteotomy. The authors will review the literature, cause, clinical presentation, prevention, and surgical management of flat-back syndrome.

Back Pain↗
PubMed2003

Accuracy of thoracic vertebral body screw placement using standard fluoroscopy, fluoroscopic image guidance, and computed tomographic image guidance: a cadaver study.

STUDY DESIGN: A surgical simulation study in human cadaver spine specimens was conducted to evaluate the accuracy of thoracic vertebral body screw placement using four different intraoperative imaging techniques. OBJECTIVE: To compare standard fluoroscopy, fluoroscopy-based image guidance with two different referencing methods, and computed tomography-based image guidance by the measuring the time required for screw placement, the radiation exposure to specimen and surgeon, and the accuracy of screw position in the thoracic spine. SUMMARY OF BACKGROUND DATA: Image guidance provides additional anatomic information to the surgeon and may improve safety of technically difficult surgical procedures. The placement of screws in the thoracic spine is a technically demanding procedure in which inaccurate screw positioning places the spinal cord, nerve roots, and paraspinal structures such as the aorta and pleural space at risk for injury. Image-guided surgery may improve the accuracy of thoracic screw placement. METHODS: Using four different intraoperative imaging methods, two experienced surgeons placed 337 vertebral body screws through the pedicles of thoracic vertebrae in 20 human cadaver thoracic spine specimens. The specimens then were examined with radiographs, computed tomography, and anatomic dissection to determine screw position. Measurements included procedure setup and screw insertion time, radiation exposure to the specimen, the surgeon's hand, the surgeon's body, frequency, direction, and magnitude of screw perforation through the cortical margins of thoracic vertebrae. RESULTS: As compared with surgery using standard fluoroscopy, fluoroscopy-based image guidance that uses multiple reference marks and computed tomography-based image guidance improves the accuracy of thoracic vertebral body screws, but increases the time required for screw placement and the specimen radiation exposure. Exposure to radiation is minimal at the surgeon's body level and dependent on surgical technique at the surgeon's hand level. Screw perforation occurs most frequently in the lateral direction. CONCLUSIONS: Fluoroscopy-based image guidance that uses only a single reference marker for the entire thoracic spine is highly inaccurate and unsafe. Systems with registration based on the instrumented vertebrae provide more accurate placement of thoracic vertebral body screws than standard fluoroscopy, but expose the patient to more radiation and require more time for screw insertion.

Adult↗
PubMed2003

Pediatric spinal deformities.

Pediatric spinal deformity results from multiple conditions including congenital anomalies, neuromuscular disorders, skeletal dysplasia, and developmental disorders (idiopathic). Pediatric spinal deformities can be progressive and cause pulmonary compromise, neurological deficits, and cardiovascular compromise. The classification and treatment of these disorders have evolved since surgical treatment was popularized when Harrington distraction instrumentation was introduced. The advent of anterior-spine instrumentation systems has challenged the concepts of length of fusion needed to arrest curvature progression. Segmental fixation revolutionized the surgical treatment of these deformities. More recently, pedicle screw-augmented segmental fixation has been introduced and promises once again to shift the standard of surgical therapy. Recent advances in thoracoscopic surgery have made this technique applicable to scoliosis surgery. Not only has surgical treatment progressed but also the classification of different forms of pediatric deformity continues to evolve. Recently, Lenke and associates proposed a new classification for adolescent idiopathic scoliosis. This classification attempts to address some of the shortcomings of the King classification system. In this article the authors review the literature on pediatric spinal deformities and highlight recent insights into classification, treatment, and surgery-related complications.

Adolescent↗
PubMed2003

Direct repair of the pars interarticularis for spondylolysis and spondylolisthesis.

Spondylolysis and spondylolisthesis can be associated with significant low back pain, especially in physically active adolescents. Non-operative management is usually successful in improving symptoms, but surgical intervention is occasionally required for those that fail reduction of activity and bracing. In a subpopulation of these patients, direct repair of the pars interarticularis defect can be an effective modality of treatment. The advantage of direct pars repair over intertransverse fusion with or without segmental instrumentation is the preservation of the anatomic integrity and motion of the affected segment. We describe our experience in 5 patients (aged 15-18 years) managed by direct pars interarticularis repair after failing multimodality non-operative treatment. The length of stay averaged 3.2 days (range 3-4 days). All 5 patients were able to return to full activity with either no (60%) or minor (40%) symptoms. No immediate or delayed complications were noted. Patients were followed a minimum of 30 months (range 30-78 months). All 5 patients demonstrated evidence of bony fusion by radiographic criteria. This demonstrates that direct pars repair is a safe and effective modality to treat select groups of patients with spondylolysis and low-grade spondylolisthesis.

Adolescent↗
PubMed2003

A cost analysis of bone morphogenetic protein versus autogenous iliac crest bone graft in single-level anterior lumbar fusion.

An economic model was developed to compare costs of stand-alone anterior lumbar interbody fusion with recombinant human bone morphogenetic protein 2 on an absorbable collagen sponge versus autogenous iliac crest bone graft in a tapered cylindrical cage or a threaded cortical bone dowel. The economic model was developed from clinical trial data, peer-reviewed literature, and clinical expert opinion. The upfront price of bone morphogenetic protein (3380 dollars) is likely to be offset to a significant extent by reductions in the use of other medical resources, particularly if costs incurred during the 2 year period following the index hospitalization are taken into account.

Bone Morphogenetic Protein 2↗
PubMed2002

Triage for the neurosurgeon.

Triage for the neurosurgeon is a misnomer. The neurosurgeon's role within a mass-casualty situation is one of a subspecialist surgeon instead of a triage officer. Unfortunately because of the events of September 11, 2001, civilian neurosurgeons and other medical specialists have been questioning their role within a mass-casualty situation or, worse, a situation created by biological, chemical, or nuclear weapons. There is no single triage system used exclusively within the United States, and different systems have differing sensitivities, specificities, and labeling methods. The purpose of this article is to discuss varying aspects of triage for both military personnel and civilians and suggest how the neurosurgeon may help shape this process within his or her community. Furthermore, the effects of biological, chemical, and nuclear weapons will be discussed in relation to the triage system.

Disaster Planning↗