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Biomedical subjects

L G Lenke

Publications and source records attributed to L G Lenke.

At least 73 records · Page 4Linked to original sources
PubMed1996

Torulopsis glabrata spinal osteomyelitis involving two contiguous vertebrae. A case report.

STUDY DESIGN: A case report and literature review of the five previous case reports. OBJECTIVES: To outline the features of Torulopsis glabrata spinal osteomyelitis, including its risk factors, diagnosis, and recommended treatments. SUMMARY OF BACKGROUND DATA: Fungal infections in general and Torulopsis glabrata in particular are becoming increasingly prevalent. Involvement of the spine will likely be more common in the future. METHODS: The literature was exhaustively reviewed and the five previous reported cases of Torulopsis glabrata identified and evaluated. This case report is analyzed in the context of the previous five cases. RESULTS: All patients responded to treatment, which varied from medical alone to medical with operative debridement and spinal fusion. CONCLUSION: Various risk factors that predisposed patients to Torulopsis glabrata osteomyelitis were present in all known cases. Diagnosis should rely on examination, history, and radiographic and laboratory evaluations. Medical therapy should be the initial treatment in most cases; however, operative intervention may be needed in patients who do not respond appropriately.

Aged↗
PubMed1996

Validity and reliability of spinal cord monitoring in neuromuscular spinal deformity surgery.

Somatosensory evoked potentials (SSEPs) have become a standard of care in surgery for spinal deformity. Recent reports in the literature have suggested SSEP monitoring is not efficacious in surgeries for patients with neuromuscular disease. Electrophysiologic data were retrospectively analyzed from 74 patients with various neuromuscular disorders undergoing spinal-deformity surgery from 1989 through February 1995 at this medical center. The monitoring protocol included SSEPs recorded from multiple sites located cortically, subcortically, and peripherally. Neurogenic motor evoked potentials (NMEPs) were also employed. Anesthetic regimens were controlled for compatibility with evoked potential monitoring. Use of this intraoperative monitoring protocol resulted in reliable data for 95% of the patient population having baseline responses. Findings suggest that evoked potentials can be used effectively during surgery for neuromuscular spinal deformity. Use of a specific protocol allowed acquisition of reliable data intraoperatively, suggesting these methods are a valid means of monitoring neurologic status.

Adolescent↗
PubMed1995

Triggered electromyographic threshold for accuracy of pedicle screw placement. An animal model and clinical correlation.

STUDY DESIGN: This study consisted of a laboratory investigation of triggered electromyographic stimulation of pedicle screws placed in a pig spine, with a correlative prospective clinical series of lumbosacral pedicle screws stimulated in a similar fashion. OBJECTIVES: To determine the threshold of stimulus intensity necessary to confirm accuracy of lumbar pedicle screw placement via a triggered electromyographic peripheral response. SUMMARY OF BACKGROUND DATA: Documentation of lumbar pedicle screw placement is imperative to perform proper spinal instrumentation and to avoid perioperative complications. Previous electrophysiologic techniques using stimulation of a pedicle opening or pedicle screw with peripheral recording of electromyographic activity from the lower extremity muscles have been used to identify varying threshold values that indicate a break in the bony pedicle wall. METHODS: Six adult pigs had 107 pedicle screws placed bilaterally into the pedicles of the lumbar spine. These screws were stimulated with an ascending stimulus intensity until a peripheral triggered electromyographic response was recorded. Pedicle screws were placed in the pig either entirely in the pedicle (Group A), medial to the pedicle without direct contact to the nerve root and dura (Group B), or purposely medial to the pedicle with direct contact to the nerve root and dura (Group C). A correlative clinical series of 233 pedicle screws placed in 54 patients had a similar intraoperative neurophysiologic technique. RESULTS: In the animal model, the mean threshold differences were: Group A screws 21.9 mA, Group B screws 8.5 mA, and Group C screws 4.2 mA (P < 0.05). Ninety-three percent of the clinical Group A screws had threshold stimuli less than 8.0 mA, whereas Groups B and C screws had a mean threshold of 3.3 mA. CONCLUSIONS: Triggered electromyographic stimulation is a valuable aid to determine appropriate placement of pedicle screws. We recommend the following interpretation of threshold stimulus intensity: > 8 mA--screw entirely in the pedicle; 4.0-8.0 mA--potential for pedicle wall defect; < 4.0 mA--strong likelihood of pedicle wall defect with potential for nerve root and dura contact.

Animals↗
PubMed1995

Analysis of pulmonary function and chest cage dimension changes after thoracoplasty in idiopathic scoliosis.

STUDY DESIGN: A prospective study of 19 adolescents and seven adults with idiopathic scoliosis undergoing posterior spinal fusion with segmental spinal instrumentation and a concomitant thoracoplasty had pulmonary function evaluation before surgery and at selected time points up to a minimum 2 years after surgery. OBJECTIVES: The objectives were to determine the effects thoracoplasty had on pulmonary function and chest cage dimension changes at a minimum 2-year follow-up in idiopathic scoliosis patients. SUMMARY OF BACKGROUND DATA: The cosmetic benefits of thoracoplasty on the rib hump deformity are well accepted. The rib resection procedure allowed for procurement of autogenous bone used for the arthrodesis. Short- and long-term pulmonary function evaluation was necessary to determine proper patient selection and any potential sequelae from the rib resection procedure. METHODS: All patients had pulmonary function tests consisting of forced vital capacity, forced expiratory volume in 1 second, and total lung capacity performed before surgery and 3 months, 1 year, and 2 years after surgery. Ten adolescents also had computed tomographic scans before and after surgery to evaluate chest cage dimension changes after the procedure. RESULTS: The 3-month postoperative pulmonary function test values of the 19 adolescents experienced a statistically significant decline, averaging 16% (P < 0.05), however, the mean values for each parameter returned to just slightly below the preoperative value at 2-years follow-up. The pulmonary function test values of the seven adults experienced a 27% initial decline 3 months after surgery and a residual 23% decline 2 years after surgery; both values were statistically significant (P < 0.05). CONCLUSIONS: We reserve the thoracoplasty procedure for adolescents and adults with preoperative pulmonary function values that will tolerate the morbidity associated with the rib resection. Adolescent patients appear to normalize their pulmonary function tests by 2 years follow-up, whereas long-term pulmonary function in the adult patient remains a concern.

Adolescent↗
PubMed1995

An analysis of sagittal spinal alignment in 100 asymptomatic middle and older aged volunteers.

STUDY DESIGN: A radiographic evaluation of 100 adult volunteers over age 40 and without a history of significant spinal abnormality was done to determine indices of sagittal spinal alignment. OBJECTIVES: To determine the sagittal contours of the spine in a population of adults older than previously reported in the literature and to correlate age and overall sagittal balance to other measures of segmental spinal alignment. SUMMARY OF BACKGROUND DATA: Previous studies of sagittal alignment have focused on adolescent and young adult populations before the onset of degenerative changes that may affect sagittal alignment. METHODS: Radiographic measurements were collected and subjected to statistical analysis. RESULTS: Mean sagittal vertical axis fell 3.2 +/- 3.2 cm behind the front of the sacrum. Total lumbar lordosis (T12-S1) averaged -64 degrees +/- 10 degrees. Lordosis increased incrementally with distal progression through the lumbar spine. Lordosis at L5-S1 and the position of the apices of the thoracic and lumbar curves were most closely correlated to sagittal vertical axis. Increasing age correlated to a more forward sagittal vertical axis with loss of distal lumbar lordosis but without an increase in thoracic or thoracolumbar kyphosis. CONCLUSIONS: The majority of asymptomatic individuals are able to maintain their sagittal alignment despite advancing age. Loss of distal lumbar lordosis is most responsible for sagittal imbalance in those individuals who do not maintain sagittal alignment. Spinal fusion for deformity should take into account the anticipated loss of lordosis that may occur with age.

Adult↗
PubMed1995

Prospective analysis of nutritional status normalization after spinal reconstructive surgery.

STUDY DESIGN: A prospective analysis of nutritional status after surgery in 57 spinal reconstructive surgery patients. OBJECTIVES: To determine the length of time required for patients to return to their preoperative nutritional baseline and to investigate risk factors for patients with prolonged normalization. SUMMARY OF BACKGROUND DATA: The preoperative nutritional status of spinal reconstructive surgery patients appears to be an important parameter of surgical morbidity, complication rates (especially wound healing), patient acceptance, and overall surgical success. METHODS: The nutritional parameters of albumin, pre-albumin, total protein, transferrin, and the absolute lymphocyte count were investigated before surgery and at various time points after surgery. RESULTS: Forty-four patients (Group A) with an average 6.4 fusion levels returned to their preoperative baseline nutritional values by 6 weeks after surgery, whereas 13 patients (Group B) with a statistically increased number of fusion levels of 13.8 (P = 0.0009) took 12 weeks or longer to return to their preoperative baseline. Risk factors for prolonged normalization (Group B) included increased total number of fusion levels, especially 10 or more (P < 0.05); patients undergoing circumferential fusions (P < 0.05); and, to a lesser extent, older patients undergoing multiple fusion levels (P = 0.055). CONCLUSIONS: These data are important when counseling spinal reconstructive surgery patients before surgery and provides information to those patients who may benefit from perioperative nutritional supplementation.

Adolescent↗
PubMed1995

Anterior fresh frozen structural allografts in the thoracic and lumbar spine. Do they work if combined with posterior fusion and instrumentation in adult patients with kyphosis or anterior column defects?

STUDY DESIGN: This was a prospective study of 24 adult patients with kyphosis or anterior column spinal defects treated with anterior fresh frozen allograft for anterior column defects and posterior instrumentation and autogenous grafting. OBJECTIVES: The objectives of the study were to assess the effectiveness of the anterior allograft in maintaining sagittal correction and to assess anterior incorporation. SUMMARY OF BACKGROUND DATA: Twenty-four patients were followed for a minimum of 2 years (range, 2 + 0-5 + 4 years). METHODS: Upright radiographs were analyzed before surgery, immediately after surgery, and at the final follow-up examination to assess success of anterior fusion and maintenance of correction. A strict four-point grading system was used. Two independent observers analyzed the radiographic results. RESULTS: Only two patients showed some collapse of their anterior allograft. The other 22 patients maintained correction, attaining a Grade I or Grade II fusion. Semiconstrained instrumentation ws used posteriorly in the two patients who had graft collapse. CONCLUSIONS: Anterior structural allograft worked effectively to maintain correction of kyphosis if combined with posterior instrumentation and autogenous grafting. Rigid forms of posterior instrumentation were preferred.

Adult↗
PubMed1995

A 13-year-old boy with rapidly progressive spinal deformity.

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to the orthopedic surgeon. Initial history, physical findings, and roentgenographic examinations are found on the first page. The final clinical and roentgenographic differential diagnoses are presented on the following pages.

Adolescent↗
PubMed1994

Posterior spinal fusion supplemented with only allograft bone in paralytic scoliosis. Does it work?

STUDY DESIGN: The authors prospectively evaluated 40 patients with paralytic scoliosis treated from 1985 to 1990 with bilateral posterior segmental instrumentation, facet fusions, local bone graft, and allograft (mostly fresh frozen) bone supplementation only. OBJECTIVES: The authors report the fusion results for these patients, and any complications referable to the use of bank bone. SUMMARY OF BACKGROUND DATA: Acceptable correction was obtained and maintained in the coronal and sagittal planes for all but two patients (the third patient with a pseudarthrosis had not lost correction). The definite pseudarthrosis rate was 7.5%. One patient had a deep wound infection. METHODS: The radiographs were graded as definitely solid, definitely a pseudarthrosis, or no instrumentation failure but difficult to visualize the whole fusion mass. The patients selected for fusion without autogenous harvesting were especially frail and had reduced pulmonary and nutritional reserve. Follow-up ranged from 2 + 2 years to 7 + 6 years, with an average of 3 + 9 years. RESULTS: In the 40 surgical patients, there were three known pseudarthroses. In 28 patients, there was a definite fusion. In the remaining nine patients (five with flaccid disease, four with spastic disease), the quality of their bone precluded definitive determination, but there was no obvious instrumentation failure or loss of correction. CONCLUSION: This study suggests that allograft bone graft is a suitable substitute for autogenous bone graft harvesting in select patients with paralysis in whom autogenous harvesting is not feasible.

Adolescent↗
PubMed1994

Astrocyte response and transforming growth factor-beta localization in acute spinal cord injury.

STUDY DESIGN: An experimental histologic and immunohistological investigation of acute spinal cord injury was performed in a rat model. OBJECTIVE: This study determined (1) the immediate cellular and molecular responses within the spinal cord that result from a clinically relevant compression injury, (2) the acute astrocytic response to injury using the astrocyte specific GFAP antibody, and (3) the temporal pattern of cellular and extracellular localization of transforming growth factor-beta 1 (TGF-beta 1) within the spinal cord injury zone immediately after injury. SUMMARY OF BACKGROUND DATA: Ultimate neurologic outcome from spinal cord injury results from both the primary mechanical trauma and a subsequent cascade of cellular and molecular events that are termed the secondary injury. Efforts aimed at improving neurologic outcome may depend on the manipulation of cellular and molecular mechanisms that are responsible for propagating this secondary injury cascade. Astrocytes and TGF-beta are two potentially key components of this secondary injury. METHODS: Twenty-one Sprague-Dawley adult rats underwent open thoracic spinal cord injuries using the Allen weight-drop technique. Spinal cord specimens were harvested at 0, 1, 2, 4, 8, 24, and 72 hours after injury for histologic and immunohistochemical evaluation. Harvesting of injured and surrounding uninjured cord was performed before sectioning in sagittal and transverse planes. These paraffin-embedded sections were stained with polyclonal antibodies against glial fibrillary acidic protein (GFAP, an astrocytic cytoskeleton marker) and TGF-beta 1. RESULTS: A complex astrocytic response to the spinal cord injury was found within 24 hours of injury. Both the geographic and temporal patterns of astrocyte localization suggest a role in the regulation of spinal cord injury propagation. High concentrations of extracellular TGF-beta were seen immediately after injury within the hematoma at the zone of impact. Subsequently, intracellular TGF-beta was seen in astrocytic nuclei and cytoplasm, intramedullary and extramedullary capillary endothelial cells, and in motor neurons. CONCLUSIONS: The neurologic outcome in patients with SCI results in part from a secondary injury whose cellular and molecular mechanisms are poorly understood. This study suggests that both astrocytes and TGF-beta are involved in the regulation of spinal cord secondary injury. An improved understanding of their specific roles may result in novel treatments to improve the outcome from SCI.

Acute Disease↗
PubMed1994

Recognition and treatment of the proximal thoracic curve in adolescent idiopathic scoliosis treated with Cotrel-Dubousset instrumentation.

STUDY DESIGN: A retrospective radiographic and clinical review of a consecutive series of patients with adolescent idiopathic scoliosis (AIS) instrumented/fused with Cotrel-Dubousset instrumentation (CDI) was undertaken. OBJECTIVE: The authors determined criteria when the upper thoracic curve should be instrumented/fused in AIS treated with CDI and assessed the results of surgical treatment. SUMMARY OF BACKGROUND DATA: Failure to recognize and include the upper left thoracic curve in the instrumentation/fusion of a lower right thoracic idiopathic scoliosis may produce shoulder imbalance and coronal decompensation. Patients with an elevated left shoulder clinically or a positive T1 tilt radiographically usually require instrumentation/fusion of the proximal thoracic curve. However, the upper left thoracic curve may be structural and require inclusion in the instrumentation/fusion when the shoulders clinically are level or even if the right shoulder is elevated preoperatively when using CDI. METHODS: The authors compared 27 patients with AIS with structural upper thoracic curves that were instrumented with CDI to T2 (Group I) to 27 patients with King Type III curves treated with CDI that did not have the upper thoracic curve instrumented/fused (Group II). RESULTS: The distinguishing Group I preoperative criteria indicating a structural upper thoracic curve included a proximal thoracic curve greater than 30 degrees that corrected to no better than 20 degrees on sidebending; > or = Grade I rotation or > or = 1 cm translation present at the apex of this curve; any elevation of the left shoulder or tilt of T1 into the concavity of the upper thoracic curve; or when the transitional vertebra between the two curves is at T6 or below. CONCLUSIONS: When these aforementioned criteria are present and surgical correction with CDI is planned, we recommend extending the instrumentation up to T2 to produce level shoulders and maintain coronal balance.

Adolescent↗
PubMed1994

Preoperative spinal canal investigation in adolescent idiopathic scoliosis curves > or = 70 degrees.

STUDY DESIGN: This is a prospective evaluation of a consecutive series of patients with adolescent idiopathic scoliosis (AIS) with curves > or = 70 degrees. OBJECTIVE: The authors investigated the possibility that large curve size may constitute an atypical presentation of idiopathic scoliosis suggestive of underlying neurologic pathology, which would warrant preoperative investigation. SUMMARY OF BACKGROUND DATA: The potential for intraspinal pathology to cause scoliosis is well accepted. The incidence of spinal canal abnormalities in congenital or atypical scoliosis may be as high as 30-60%. Identification of clinical neurologic deficits, congenital abnormalities, or atypical features of scoliosis are often helpful in identifying the subpopulation of scoliosis patients at risk for spinal canal pathology. METHODS: Thirty-three consecutive patients with large (> or = 70 degrees) adolescent idiopathic scoliosis (AIS) and without evidence of neurologic or congenital abnormalities, were evaluated with either computed tomography/myelogram (n = 3) or magnetic resonance imaging (n = 30) to assess the entire spinal canal. RESULTS: None of the studies revealed any pathology of the neuraxis, and all 33 patients were treated with surgery without any neurologic sequelae. CONCLUSIONS: Preoperative investigation of the central neuraxis is not mandatory in large (> or = 70 degrees) but otherwise typical AIS curves. These large curves do not appear to suggest associated spinal canal anomalies.

Adolescent↗
PubMed1994

Diagnosis of perioperative myocardial infarction with measurement of cardiac troponin I.

BACKGROUND: Perioperative myocardial infarction is the most common cause of morbidity and mortality in patients who have had noncardiac surgery, but its diagnosis can be difficult. The present study was designed to determine whether the measurement of serum levels of cardiac troponin I, a highly sensitive and specific marker for cardiac injury, would help establish the diagnosis of myocardial infarction. METHODS: We obtained preoperative measurements of MB creatine kinase, total creatine kinase, and cardiac troponin I, in addition to base-line electrocardiograms and two-dimensional echocardiograms, in 96 patients undergoing vascular surgery and 12 undergoing spinal surgery. Blood samples were obtained every 6 hours for at least the first 36 hours after surgery, and electrocardiograms were obtained daily; a second echocardiogram was obtained approximately three days after surgery. The appearance of a new abnormality in segmental-wall motion on the postoperative echocardiogram (that is, an abnormality that had not been seen on the preoperative echocardiogram) was considered to be indicative of perioperative infarction. RESULTS: Eight patients who underwent vascular surgery had new abnormalities in segmental-wall motion and received a diagnosis of perioperative infarction. All eight had elevations of cardiac troponin I, and six had elevations of MB creatine kinase. Of the 100 patients without perioperative infarction detected by echocardiography, 19 had elevations of MB creatine kinase, and 1 had a slight elevation of cardiac troponin I. CONCLUSIONS: The measurement of cardiac troponin I is a sensitive and specific method for the diagnosis of perioperative myocardial infarction. It avoids the high incidence of false diagnoses associated with the use of MB creatine kinase as a diagnostic marker.

Creatine Kinase↗
PubMed1994

Increase in creatine kinase MB isoenzyme levels after spinal surgery.

Serial assays of creatine kinase (CK) and particularly its isoenzyme CK-MB are the tests of choice for the laboratory confirmation of myocardial tissue damage. However, elevations attributable to skeletal muscle injury also have been reported, and we noted elevated levels of total CK, CK-MB, and percent MB postoperatively following spinal surgery in some of our patients. To define prospectively the frequency of elevations and their clinical correlates, we studied 20 consecutive spinal surgical procedures in 17 adults. Postoperative elevations of CK-MB occurred in 55% of these procedures in the absence of overt clinical signs of myocardial injury. Elevations were correlated with operative time and the length of the surgical dissection. These data confirm that elevations in CK-MB and percent MB can occur after spinal surgery in the absence of overt clinical manifestations of myocardial injury. Thus, enzyme elevations should not be used in isolation to diagnose myocardial infarction in these patients.

Adult↗
PubMed1994

Intracanalicular osteochondroma producing spinal cord compression in hereditary multiple exostoses.

Spinal cord compression is an unusual but potentially catastrophic manifestation of hereditary multiple exostoses (HMEs). Isolated, osteochondromas are usually of little significance. However, if they are located near neurologic structures, they may cause irritation due to mechanical compression. In patients with HMEs who present with neck or back pain, and particularly in those who have neurologic symptoms in the upper or lower extremities, a diagnosis of intracanalicular osteochondroma should be presumed until proven otherwise. Prompt diagnosis and surgical excision affords the best prognosis for these patients who have spinal cord compression secondary to intracanalicular osteochondroma.

Adolescent↗
PubMed1994

Evoked potential monitoring of the upper extremities during thoracic and lumbar spinal deformity surgery: a prospective study.

We prospectively investigated the usefulness of somatosensory evoked potential (SEP) monitoring to detect clinically significant peripheral nerve or brachial plexus compression in the upper extremities during spinal deformity surgery. All patients had bilateral median and ulnar nerve SEPs evaluated as a baseline, both intermittently throughout the surgical procedure and at termination of surgery. This information was correlated with pre- and postoperative upper extremity neurologic examinations. Twenty-five upper extremities in 21 patients had intraoperative SEP changes consisting of at least a 60% decline in amplitude or a 10% increase in latency. On many occasions, repositioning of the upper extremities improved the SEP responses to acceptable baselines. Overall, SEP monitoring of the upper extremities was 78% sensitive for detecting upper extremity sensory deficits, 100% sensitive for detecting combined sensory and motor deficits, and 98.5% specific for predicting normal postoperative upper extremity function. We recommend the simultaneous electrophysiologic monitoring of the upper and lower extremities during spinal surgery to allow identification of brachial plexus and/or peripheral nerve stretch/compression that may be amenable to intraoperative correction.

Adolescent↗