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Biomedical subjects

Kevin T Foley

Publications and source records attributed to Kevin T Foley.

7 recordsLinked to original sources
PubMed2003

Minimally invasive lumbar fusion.

STUDY DESIGN: Review article. OBJECTIVES: To provide an overview of current techniques for minimally invasive lumbar fusion. SUMMARY OF BACKGROUND DATA: Minimally invasive techniques have revolutionized the management of pathologic conditions in various surgical disciplines. Although these same principles have been used in the treatment of lumbar disc disease for many years, minimally invasive lumbar fusion procedures have only recently been developed. The goals of these procedures are to reduce the approach-related morbidity associated with traditional lumbar fusion, yet allow the surgery to be performed in an effective and safe manner. METHODS: The authors' clinical experience with minimally invasive lumbar fusion was reviewed, and the pertinent literature was surveyed. RESULTS: Minimally invasive approaches have been developed for common lumbar procedures such as anterior and posterior interbody fusion, posterolateral onlay fusion, and internal fixation. As with all new surgical techniques, minimally invasive lumbar fusion has a learning curve. As well, there are benefits and disadvantages associated with each technique. However, because these techniques are new and evolving, evidence to support their potential benefits is largely anecdotal. Additionally, there are few long-term studies to document clinical outcomes. CONCLUSIONS: Preliminary clinical results suggest that minimally invasive lumbar fusion will have a beneficial impact on the care of patients with spinal disorders. Outcome studies with long-term follow-up will be necessary to validate its success and allow minimally invasive lumbar fusion to become more widely accepted.

Animals↗
PubMed2003

Minimally invasive fusion: summary statement.

Ideally, minimally invasive surgery (MIS) allows less extensive manipulation of surrounding tissues than a conventional open procedure while accomplishing the same goals and objectives at the target structure. Long-term follow-up combined with appropriate outcome measures are necessary to prove the safety and effectiveness of MIS. For MIS procedures to be widely adopted, they must have an acceptable learning curve. Special skills are needed and are beyond those of traditional open surgery, By definition, as compared with conventional open surgeries, minimally invasive procedures typically involve smaller incisions and less extensive surgical manipulation of the tissues that surround the target structure. Ideally, once the target structure has been reached, the minimally invasive procedure should accomplish the same goals and objectives as its open surgical counterpart. Thus, although minimally invasive surgeries are aimed at reducing the morbidity associated with open surgical approaches, they should not hinder the surgeon's ability to perform a successful operation. In other words, minimal invasion should not equate to minimally effective.

Clinical Competence↗
PubMed2003

Intraoperative spinal navigation.

STUDY DESIGN: Review article. OBJECTIVES: To provide a detailed overview of current methods for intraoperative spinal navigation using image-guided surgical technology. SUMMARY OF BACKGROUND DATA: The development of novel intraoperative navigational techniques has been an important advancement in the field of spine surgery. These techniques, commonly referred to as image-guided surgery (IGS), provide simultaneous, multiplanar views of spinal anatomy. They can be used for detailed preoperative planning and allow the spinal surgeon to track the position of surgical instruments in real time. IGS technology can increase the accuracy of spinal instrumentation procedures and improve patient safety. METHODS: The relevant medical literature was reviewed, as was the authors' clinical and laboratory experience with intraoperative spinal navigation. RESULTS: Image-guided spinal instrumentation procedures in the cervical, thoracic, and lumbar spine have lower rates of screw misplacement than do those performed without image guidance. In a typical IGS spinal procedure, surgical instruments are tracked in the operating room, and their positions are superimposed onto preoperatively acquired computed tomography scans (CT-based image guidance) or intraoperatively acquired fluoroscopic images (virtual fluoroscopy). A new development, the combination of isocentric C-arm fluoroscopy with computer-assisted image guidance, allows the C-arm to create intraoperative CT images that can be used for image-guided navigation without the need for a surgeon-dependent registration step. Each of these technologies has distinct advantages and limitations. CONCLUSIONS: Intraoperative spinal navigation has advanced rapidly in recent years, beneficially affecting a variety of surgical procedures. Future technological developments will widen its clinical application and minimize its shortcomings.

Adult↗
PubMed2002

Influence of lower extremity strength of healthy older adults on the outcome of an induced trip.

OBJECTIVES: To determine whether decreased lower extremity strength contributes to trip-related falls in older adults. DESIGN: A cross-sectional sample of older adults were safety-harnessed and tripped while walking using a concealed, mechanical obstacle. Lower extremity strength was compared between trip outcome groups. SETTING: A biomechanics research laboratory. PARTICIPANTS: Seventy-nine healthy, community-dwelling adults aged 65 and older (50 women). MEASUREMENTS: Ankle, knee, and hip flexion and extension strength were measured isometrically and isokinetically. Measured strengths were subjected to a factor analysis. Strength factor scores were compared between those who recovered from the trip and those who fell by three previously identified mechanisms: during-step, after-step, and elevating-response falls. RESULTS: Seven common factors, one associated with each direction of exertion at each joint and one with the time rate of moment increase, explained 88% of the variance in measured strength. The during-step (n=5) fallers were significantly stronger in the ankle extension (plantarflexion), knee flexion, overall extension, and total strength factors than those who successfully recovered using a similar, lowering strategy (n=26). The elevating-response faller (n=1) was stronger in the plantarflexion and overall extension factors than most of those who recovered using a similar, elevating strategy (n=11). Two of three after-step fallers were among the weakest subjects tested. CONCLUSION: Weak older adults and the strongest older adults may be at greater risk of falling from a trip, although by different mechanisms. High strength may increase the likelihood of a during-step or elevating-response fall; decreased strength may increase the likelihood of an after-step fall.

Accidental Falls↗
PubMed2002

Percutaneous pedicle screw fixation of the lumbar spine: preliminary clinical results.

OBJECT: Standard techniques for pedicle screw fixation of the lumbar spine involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine. METHODS: An existing multiaxial lumbar pedicle screw system was modified to allow screws to be placed percutaneously by using an extension sleeve that permits remote manipulation of the polyaxial screw heads and remote engagement of the screw-locking mechanism. A unique rod-insertion device was developed that linked to the screw extension sleeves, allowing for a precut and -contoured rod to be placed through a small stab wound. Because the insertion device relies on the geometrical constraint of the rod pathway through the screw heads, minimal manipulation is required to place the rods in a standard submuscular position, there is essentially no muscle dissection, and the need for direct visual feedback is avoided. Twelve patients (six men and six women) who ranged in age from 23 to 68 years underwent pedicle screw fixation in which the rod-insertion device was used. Spondylolisthesis was present in 10 patients and osseous nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5-S1, three at L4-5, and one at L2-3), and two underwent two-level fusions (one from L3-5 and the other from L4-S1). The follow-up period ranged from 10 to 19 months (mean 13.8 months). CONCLUSIONS: Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience involving the use of this device has been promising.

Adult↗
PubMed2002

Microendoscopic lumbar discectomy: technical note.

OBJECTIVE: The microendoscopic discectomy (MED) technique was initially developed in 1997 to treat herniated lumbar disc disease. Since then, thousands of cases have been successfully performed at more than 500 institutions. This article discusses the technical aspects of this procedure and presents a consecutive case series. METHODS: A total of 150 consecutive patients underwent MED. MED is performed by a muscle-splitting approach using a series of tubular dilators with consecutively increasing diameters. A tubular retractor is then inserted over the final dilator, and a specially designed endoscope is placed inside the tubular retractor. The microdiscectomy is performed endoscopically while the surgeon views the procedure on a video monitor. RESULTS: Clinical outcomes were determined using a modified MacNab criteria, which revealed that 77% of patients had excellent, 17% had good, 3% had fair, and 3% had poor outcomes. The average hospital stay was 7.7 hours. The average return to work period was 17 days. Complications primarily included dural tears, which occurred in 8 patients (5%) and were seen early on in the patient series. Complication rates diminished as the surgeon's experience with this technique increased. CONCLUSION: MED for lumbar herniated disc disease can be performed safely and effectively, resulting in a shortened hospital stay and faster return to work; however, there is a learning curve to this procedure.

Adult↗