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Biomedical subjects

G E Lutz

Publications and source records attributed to G E Lutz.

10 recordsLinked to original sources
PubMed2001

Stability of the lumbar spine after intradiscal electrothermal therapy.

OBJECTIVE: To assess the stability of the human lumbar cadaveric spinal motion segment before and after treatment with intradiscal electrothermal therapy (IDET). DESIGN: An in vitro biomechanic analysis of 5 human cadaveric spinal motion segments by using nondestructive biomechanic testing in flexion/extension, lateral bending, and axial rotation with loads of 0N, 600N, and 1200N. SETTING: University-based hospital research center. CADAVERS: Spinal unit specimens (upper and middle lumbar) from 5 human cadavers (age range, 39-79yr). INTERVENTIONS: A spinal catheter consisting of a thermal-resistive heating coil was placed circumferentially into the outer annulus by using the standard extrapedicular discographic technique through a 17-gauge introducer needle. The disc was then heated in a saline bath (37 degrees C) from 65 degrees C up to 90 degrees C for a total of 17 minutes. MAIN OUTCOME MEASURE: The stability of the spinal segments was measured before and shortly after IDET. Stability of the spine was measured as the compliance of the spine (the angular deformation afforded by the spine under applied bending moments). RESULTS: With increasing preloads, there is a decrease in motion of the spinal segment in all planes of testing. However, there was no significant difference (p >.05) in the stability of the lumbar spine before and after treatment with IDET. CONCLUSIONS: IDET does not destabilize the spinal motion segment in vitro.

Adult↗
PubMed2001

Intradiskal electrothermal therapy: a preliminary histologic study.

OBJECTIVE: To characterize descriptively the histologic and temperature effects of intradiskal electrothermal annuloplasty on human cadaveric lumbar disks. DESIGN: In vitro histologic study. SETTING: Hospital-based soft-tissue research laboratory. CADAVERS: Six human cadaveric lumbar disks, from 5 cadavers aged 39 to 79 who died from nonspine-related causes. INTERVENTIONS: Intradiskal electrothermal therapy (IDET) by using a standard high-temperature heating protocol with the temperature of the probe gradually increased from 65 degrees C to 90 degrees C over 16.5 minutes. Disks were stained and examined by light microscopy and electron microscopy. MAIN OUTCOME MEASURES: Temperatures in outer annulus, gross macroscopic changes, and histologic damage. RESULTS: Gross inspection showed a small circumferential area of tissue alteration localized to the posterior annulus but not extending to the endplates. Light microscopy of the posterior aspect of the lumbar disks showed denaturation, shrinkage, and coalescence of annular collagen; the anterior portions, which served as internal controls, showed no evidence of damage. The endplates were structurally preserved and showed no evidence of damage. Electron microscopy showed extensive collagen disorganization, decreased quantity of collagen, collagen fibril shrinkage, and chondrocyte damage when compared with a control portion. The temperature curves showed parallel changes in temperature at the level of the probe and at the posterior portion of the disk. CONCLUSIONS: IDET raises temperatures sufficiently to induce collagen denaturation and coalescence. These histologic changes may play a substantial role in the clinical efficacy of IDET.

Adult↗
PubMed2000

A ganglion cyst causing lumbar radiculopathy in a baseball pitcher: a case report.

This report describes a case of a professional baseball pitcher who developed acute left lumbar radicular symptoms after a baseball game and was subsequently sidelined for the rest of the season. Physical examination revealed depressed reflexes in the left posterior tibialis and left medial hamstring muscles, mild weakness in the left extensor hallucis longus, and positive dural tension signs. Magnetic resonance imaging demonstrated an ovoid mass at the L4-L5 level, causing compression of the dura. Surgical resection of the mass resulted in resolution of his symptoms. Pathology revealed that the mass was a ganglion cyst. A ganglion cyst is a rare cause of lumbar radiculopathy and should be considered in the differential diagnosis if a patient with lumbar radiculopathy fails to respond to conservative treatment.

Adult↗
PubMed2000

Internal disc disruption and axial back pain in the athlete.

Axial back pain is commonly encountered by the sports medicine physician and has a variety of potential pain generators. Internal disc disruption is an important diagnosis to consider, particularly if there is a history of spinal trauma. The pathogenesis of IDD is not definitively known, although related theories exist. The process may begin with a vertebral endplate fracture followed by an inflammatory degradation of the disc matrix. Annular tears extend from the nucleus pulposus to the periphery and nociceptive nerve endings grow into the inner annulus and become sensitized by the biochemical degradative products. This lowers the pain threshold for mechanical stimulation during normal loading of the lumbar disc. Athletes are at high risk for IDD because of the repetitive axial compressive and torsional forces required in many sports. Diagnostic evaluation includes a thorough history and physical examination, whereas MR imaging is the modality of greatest use. Acute IDD is a symptomatic annular tear that commonly responds to aggressive conservative care delineated in the five-stage rehabilitation program. Chronic IDD may be episodic or constant. Pressure-controlled, provocative discography should be considered for athletes with chronic constant lumbar discogenic pain. Minimally invasive treatment options, such as IDET, may prove useful for a subset of patients with discographically proven IDD. Further clinical and basic science research is needed. Spinal fusion rarely is indicated for the athlete with internal disc disruption and no evidence of instability. Technological advances should continue to contribute to the arsenal of future treatments for internal disc disruption.

Acute Disease↗
PubMed1999

Sural nerve entrapment after injury to the gastrocnemius: a case report.

A 43-year-old man developed progressive calf pain and paresthesias after a strain of the right gastrocnemius muscle. Physical examination revealed sensory loss in the distribution of the sural nerve with a positive Tinel's sign in the posterior calf in the region of his previous injury. Electrodiagnostic studies revealed prolongation of the sural distal latency with reduction of the sensory nerve action potential amplitude. Magnetic resonance imaging of the lower right leg demonstrated abnormal signal in the right medial gastrocnemius consistent with a subacute hematoma. Surgical exploration revealed entrapment of the sural nerve in scar tissue beneath the deep fascia of the gastrocnemius. Surgical release of the nerve resulted in complete resolution of symptoms and full return of sensation by the 3-month follow-up point. A brief review of the literature is presented.

Action Potentials↗
PubMed1998

Fluoroscopic transforaminal lumbar epidural steroids: an outcome study.

OBJECTIVES: To determine the therapeutic value and long-term effects of fluoroscopic transforaminal epidural steroid injections in patients with refractory radicular leg pain. BACKGROUND DATA: Although numerous studies have evaluated the efficacy of traditional transsacral (caudal) or translaminar (lumbar) administration of epidural steroids, to our knowledge no studies have assessed specifically the therapeutic value of fluoroscopic transforaminal epidural steroids. STUDY DESIGN: A prospective case series that investigated the outcome of patients with lumbar herniated nucleus pulposus and radiculopathy who received fluoroscopic transforaminal epidural steroid injections. METHODS: Patients who met our inclusion criteria received fluoroscopically guided, contrast-enhanced transforaminal epidural administration of anesthetic and steroid directly at the level and side of their documented pathology. Patients were evaluated by an independent observer and received sequential questionnaires before and after injection, documenting pain level, activity level, and patient satisfaction. RESULTS: Sixty-nine patients met our inclusion criteria and were followed for an average period of 80 weeks (range, 28 to 144 weeks); 75.4% of patients had a successful long-term outcome, reporting at least a >50% reduction between preinjection and postinjection pain scores, as well as an ability to return to or near their previous levels of functioning after only 1.8 injections per patient (range, 1 to 4 injections). Of our patients, 78.3% were satisfied with their final outcomes. CONCLUSIONS: Fluoroscopic transforminal epidural steroids are an effective nonsurgical treatment option for patients with lumbar herniated nucleus pulposus and radiculopathy in whom more conservative treatments are not effective and should be considered before surgical intervention.

Adult↗
PubMed1993

Comparison of tibiofemoral joint forces during open-kinetic-chain and closed-kinetic-chain exercises.

The purpose of this study was to analyze forces at the tibiofemoral joint during open and closed-kinetic-chain exercises. Five healthy subjects performed maximum isometric contractions at 30, 60, and 90 degrees of knee flexion during open-kinetic-chain extension, open-kinetic-chain flexion, and closed-kinetic-chain exercises. Electromyographic activity of the quadriceps and hamstrings, as well as load and torque-cell data, were recorded. Tibiofemoral shear and compression forces were calculated with use of a two-dimensional biomechanical model. The results showed that, during the open-kinetic-chain extension exercise, maximum posterior shear forces (the resisting forces to anterior drawer) of 285 +/- 120 newtons (mean and standard deviation) occurred at 30 degrees of knee flexion and maximum anterior shear forces (the resisting forces to posterior drawer) of 1780 +/- 699 newtons occurred at 90 degrees of knee flexion. The closed-kinetic-chain exercise produced significantly less posterior shear force at all angles when compared with the open-kinetic-chain extension exercise. In addition, the closed-kinetic-chain exercise produced significantly less anterior shear force at all angles except 30 degrees when compared with the open-kinetic-chain flexion exercise (p < 0.05). Analysis of tibiofemoral compression forces and electromyographic recruitment patterns revealed that the closed-kinetic-chain exercise produced significantly greater compression forces and increased muscular co-contraction at the same angles at which the open-kinetic-chain exercises produced maximum shear forces and minimum muscular co-contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Rehabilitative techniques for athletes after reconstruction of the anterior cruciate ligament.

A wide spectrum of protocols is available for rehabilitation after anterior cruciate ligament reconstruction, and little agreement exists on the specifics of strengthening exercises or the sequence of activities. In this article, we discuss the current rehabilitative techniques used at the Mayo Clinic for athletes who have undergone anterior cruciate ligament reconstruction. These techniques are based on established principles of rehabilitation, clinical experience, and new information about the related biomechanics of the knee. An illustrative case reflects the benefits of this rehabilitation program, which lasts up to 1 year and is divided into five stages. The early stages focus on protected mobilization and a strengthening program that emphasizes closed rather than open kinetic chain exercises. Later, neuromuscular-proprioceptive training and sport-specific agility training redevelop the reaction time and the "coordination engrams" necessary for athletic competition. High-quality surgical care and a closely supervised rehabilitation program, based on kinesiologic and biomechanical factors as they pertain to the anterior cruciate ligament, are necessary for a successful outcome.

Adolescent↗
PubMedDate not supplied

Comparison of intersegmental tibiofemoral joint forces and muscle activity during various closed kinetic chain exercises.

The purpose of this study was to analyze intersegmental forces at the tibiofemoral joint and muscle activity during three commonly prescribed closed kinetic chain exercises: the power squat, the front squat, and the lunge. Subjects with anterior cruciate ligament-intact knees performed repetitions of each of the three exercises using a 223-N (50-pound) barbell. The results showed that the mean tibiofemoral shear force was posterior (tibial force on femur) throughout the cycle of all three exercises. The magnitude of the posterior shear forces increased with knee flexion during the descent phase of each exercise. Joint compression forces remained constant throughout the descent and ascent phases of the power squat and the front squat. A net offset in extension for the moment about the knee was present for all three exercises. Increased quadriceps muscle activity and the decreased hamstring muscle activity are required to perform the lunge as compared with the power squat and the front squat. A posterior tibiofemoral shear force throughout the entire cycle of all three exercises in these subjects with anterior cruciate ligament-intact knees indicates that the potential loading on the injured or reconstructed anterior cruciate ligament is not significant. The magnitude of the posterior tibiofemoral shear force is not likely to be detrimental to the injured or reconstructed posterior cruciate ligament. These conclusions assume that the resultant anteroposterior shear force corresponds to the anterior and posterior cruciate ligament forces.

Adult↗