Biomedical subjects

B A Green

Publications and source records attributed to B A Green.

At least 37 records · Page 2Linked to original sources

PubMed1998

Treatment of stable burst fracture of the atlas (Jefferson fracture) with rigid cervical collar.

STUDY DESIGN: A retrospective review of a clinical series. OBJECTIVE: To evaluate the use of a rigid cervical collar alone as the treatment for stable Jefferson fracture, and to devise an algorithm for treatment of Jefferson fracture with or without an associated cervical injury. SUMMARY OF BACKGROUND DATA: The traditional treatment for Jefferson fracture, if there is no indication for surgery, is immobilization by halo vest. Because halo vest placement is associated with intracranial infection and a significant degree of patient discomfort, slightly less rigid forms of external immobilization may be useful for the treatment of stable Jefferson fractures. No standard protocol calling for the use of one form of stabilization device has been reported. MATERIALS: The medical records and radiographs of 16 consecutive patients with Jefferson fracture during a 2-year period were reviewed. Each patient underwent a complete cervical radiograph series and a computed tomographic scan. The mean C1 lateral mass displacement was 1.8 mm. Cervical spine radiographs, including lateral flexion-extension views were obtained 10 to 12 weeks after injury before the removal of an external immobilization device. RESULTS: Of these 16 patients, 1 sustained a complete injury, and 7 sustained an incomplete injury. Eight patients were neurologically intact. Twelve patients sustained a stable Jefferson fracture and were treated with a rigid cervical collar (Miami-J collar [Jerome Medical, Moorestown, NJ]) alone from 10 to 12 weeks. The patient sustaining the complete neurologic injury died of multisystem trauma. All 15 live patients showed no instability on their follow-up plain radiographs before the removal of an external stabilization device. Six patients underwent further plain radiographs approximately 1 year after the fracture and similarly demonstrated no instability. CONCLUSIONS: Isolated stable burst fracture of the atlas can be treated effectively with a rigid cervical collar alone for 10 to 12 weeks with good neurologic recovery and segmental stability. Unstable Jefferson fractures with concurrent unstable fracture of other cervical vertebrae, especially C2, requires surgical stabilization.

Adolescent↗

PubMed1998

Surgical treatment of spinal ependymoma and post-operative radiotherapy.

INTRODUCTION: With the advances in microsurgical and monitoring techniques, spinal ependymomas are gross totally resected more frequently. The use of adjuvant radiotherapy has become questionable with gross total resection and its role for residual neoplasm need to be redefined. A retrospective analysis of a series of patients was carried out to investigate our clinical outcome and selected use of post-operative radiotherapy. CLINICAL MATERIALS AND METHODS: Between July 1990 and May 1995, nineteen patients [M : F = 12 : 7; age range: 21 to 71 years] with a spinal ependymoma were treated at University of Miami by the senior author. (BAG) Pre-operative MRI diagnosed the intraspinal tumor, and pathology reports demonstrated that each patient had a histologically confirmed ependymoma. At the time of diagnosis, the most common symptoms presented were pain (in 16 patients = 84.2%). The pattern of progression of clinical symptoms was directly related to the location of the tumor. Each patient had an MRI immediately after surgery, approximately 6 months post-operatively, and then annually. RESULTS: All 19 patients underwent intradural microsurgical exploration with an attempted gross total resection (achieved in 16 patients = 79%) of the ependymoma through a posterior approach. Direct neural tissue stimulation halted further resection in 2 patients with questionable tumor margins. Radiation therapy was employed as a surgical adjunct in 3 patients (15.8%) because of possible residual tumor. All patients were followed up postoperatively for an average of 50.6 months (range 6 months to 6 years). All patients are surviving to date. Surgical resection of these tumors led to significant alleviation of pre-operative symptom. There has been no radiographic evidence of tumor recurrence or growth in any patient to date. CONCLUSION: Surgical resection of spinal ependymoma leads to significant improvement of pre-operative symptoms. Surgical removal alone, with an attempt to grossly resect the tumor, should be the treatment of choice, with careful clinical and radiographic follow-up. Radiation therapy should only be considered as a surgical adjunct where gross total resection is not achieved.

Adult↗

PubMed1998

Oxyhemoglobin desaturation and aberrant carbon dioxide homeostasis during electrically stimulated exercise in a ventilator-dependent tetraplegic patient.

This single-subject case examined oxyhemoglobin saturation and alveolar end-tidal carbon dioxide levels in a ventilator-dependent tetraplegic patient undergoing electrical stimulation cycle ergometry. When exercising with a closed tracheostomy cuff under resting ventilator settings (resting intermittent mandatory ventilation; frequency = 6breaths/min, tidal volume = 83.3mL, minute ventilation =5L/min), his oxyhemoglobin saturation decreased from 100% to 92%, while alveolar endtidal carbon dioxide increased linearly to 47mmHg. These undesirable changes were corrected under adjusted intermittent mandatory ventilation conditions (frequency = 12breaths/min, tidal volume = 83.3mL, minute ventilation = 10L/min), during which oxyhemoglobin saturation remained above 98% and the alveolar end-tidal carbon dioxide trend resembled that of ventilator-independent tetraplegic individuals undergoing the same exercise. Because the subject's heart rate was higher under adjusted ventilation conditions, these responses may have been caused by augmented venous return resulting from greater abdominothoracic pumping at the higher breathing frequency. These findings support the need to modify ventilator settings in ventilator-dependent tetraplegic persons while undergoing exercise to maintain oxyhemoglobin saturation and carbon dioxide homeostasis.

Adult↗

PubMed1998

Surgery for cervical myelopathy in geriatric patients.

OBJECTIVE: The number of geriatric patients seeking surgical treatment for cervical myelopathy is steadily increasing. Although anecdotal experiences have been good, insufficient data exists in the spine literature concerning this particular group. We decided to review our experience to determine efficacy of surgical management and examine our morbidity with this select group. METHODS: We undertook a retrospective review of all surgical procedures for nontraumatic cervical myelopathy performed at Mt Sinai Medical Center and Jackson Memorial Medical Center between January 1 1987 and June 1 1992, in patients older than 70 years of age (33 men and 18 women). RESULTS: A total of 53 cervical surgical procedures were performed in 51 patients (nine expansile laminoplasties, 20 anterior cervical diskectomies and fusion and 24 decompressive posterior laminectomies). The average hospital stay was 7.7 +/- 3.4 days. Twenty-one (41%) patients required inpatient rehabilitation; the remaining 30 patients received outpatient rehabilitative therapy. The major morbidity rate was 3.9%, and the minor morbidity rate was 5.8%. Perioperative medical complications included cardiac arrhythmias, hypertensive episodes, atelectasis, confusion, urinary dysfunction and hyponatremia. All of these complications resolved except in one patient. The perioperative mortality rate was 2%. Office follow-up was performed for a mean of 11.1 +/- 2.5 months postoperatively. Comparison of preoperative and postoperative functional status was performed using Nurick's criteria as described in the literature. At follow-up, 60.8% of the patients had improvement in their myelopathic symptoms, especially in regard to gait; 33.3% were stabilized and 5.9% had worsened neurological function. CONCLUSION: This study demonstrates that corrective surgical procedures for significant nontraumatic cervical myelopathy in the geriatric population may be performed safely, that is, with acceptable risk of morbidity and reasonable expectation for clinical improvement.

Aged↗

PubMed1998

Diagnostic and surgical management of spinal dural arteriovenous fistulas.

OBJECTIVE: A retrospective review was conducted to compare magnetic resonance (MR) and conventional spinal angiographic images and to investigate the outcome of our treatment protocol for patients with spinal dural arteriovenous fistulas (DAVFs). MATERIALS AND METHODS: Nine patients with a diagnosis of DAVF based on clinical myelopathy and preoperative MR imaging (MRI) and MR angiography (MRA) findings were treated at our institution by the senior author (BAG). All nine patients initially presented with progressive myelopathy. Preoperative MRI revealed T2-weighted signal abnormalities in all patients, and MRA was diagnostic in all patients. Each patient underwent a laminectomy and ligation of the arterialized draining vein. Selective spinal angiograms were used to confirm the level of fistula immediately before the surgical procedure was performed and to document complete obliteration after clip ligation of the medullary draining vein. Follow-up MRI and MRA were performed approximately 2 months postoperatively. RESULTS: MRI T2-weighted signal hyperintensity improved after surgery in all nine patients. Postoperatively, progression of motor weakness and gait difficulty was halted and some improvement was observed in all patients. No patient was neurologically normal, however. To date, there has been no clinical or MRA evidence of recurrence in any patient. CONCLUSION: Preoperative MRA and intraoperative spinal x-ray angiography present as an effective combination for diagnosing and intraoperatively confirming DAVF. Both T1-weighted enhancement and T2-weighted signal hyperintensity on MR images improved after the obliteration of the DAVFs and correlated with clinical improvement in all nine patients. MRA provides adequate visualization and localization of spinal DAVFs and may serve as a useful noninvasive tool for diagnosing and following patients with spinal DAVFs in the future.

Adult↗

PubMed1998

"Threshold-level" multipulse transcranial electrical stimulation of motor cortex for intraoperative monitoring of spinal motor tracts: description of method and comparison to somatosensory evoked potential monitoring.

UNLABELLED: Numerous methods have been pursued to evaluate function in central motor pathways during surgery in the anesthetized patient. At this time, no standard has emerged, possibly because each of the methods described to date requires some degree of compromise and/or lacks sensitivity. OBJECT: The goal of this study was to develop and evaluate a protocol for intraoperative monitoring of spinal motor conduction that: 1) is safe; 2) is sensitive and specific to motor pathways; 3) provides immediate feedback; 4) is compatible with anesthesia requirements; 5) allows monitoring of spontaneous and/or nerve root stimulus-evoked electromyography; 6) requires little or no involvement of the surgical team; and 7) requires limited equipment beyond that routinely used for somatosensory evoked potential (SSEP) monitoring. Using a multipulse electrical stimulator designed for transcranial applications, the authors have developed a protocol that they term "threshold-level" multipulse transcranial electrical stimulation (TES). METHODS: Patients considered at high risk for postoperative deficit were studied. After anesthesia had been induced and the patient positioned, but prior to incision, "baseline" measures of SSEPs were obtained as well as the minimum (that is, threshold-level) TES voltage needed to evoke a motor response from each of the muscles being monitored. A brief, high-frequency pulse train (three pulses; 2-msec interpulse interval) was used for TES in all cases. Data (latency and amplitude for SSEP; threshold voltage for TES) were collected at different times throughout the surgical procedure. Postoperative neurological status, as judged by evaluation of sensory and motor status, was compared with intraoperative SSEP and TES findings for determination of the sensitivity and specificity of each electrophysiological monitoring technique. Of the 34 patients enrolled, 32 demonstrated TES-evoked responses in muscles innervated at levels caudal to the lesion when examined after anesthesia induction and positioning but prior to incision (that is, baseline). In contrast, baseline SSEPs could be resolved in only 25 of the 34 patients. During surgery, significant changes in SSEP waveforms were noted in 12 of these 25 patients, and 10 patients demonstrated changes in TES thresholds. Fifteen patients experienced varying degrees and durations of postoperative neurological deficit. Intraoperative changes in TES thresholds accurately predicted each instance of postoperative motor weakness without error, but failed to predict four instances of postoperative sensory deficit. Intraoperative SSEP monitoring was not 100% accurate in predicting postoperative sensory status and failed to predict five instances of postoperative motor deficit. As a result of intraoperative TES findings, the surgical plan was altered or otherwise influenced in six patients (roughly 15% of the sample population), possibly limiting the extent of postoperative motor deficit experienced by these patients. CONCLUSIONS: This novel method for intraoperative monitoring of spinal motor conduction appears to meet all of the goals outlined above. Although the risk of postoperative motor deficit is relatively low for the majority of spine surgeries (for example, a simple disc), high-risk procedures, such as tumor resection, correction of vascular abnormalities, and correction of major deformities, should benefit from the virtually immediate and accurate knowledge of spinal motor conduction provided by this new monitoring approach.

Adolescent↗

PubMed1998

Safety and stability of open-door cervical expansive laminoplasty.

Cervical expansive laminoplasty has been utilized for over 20 years. This retrospective analysis investigated the safety and incidence of postoperative instability of patients undergoing a modified expansive laminoplasty. One hundred five patients underwent a modified cervical expansive laminoplasty and had at least a 6-month follow-up. These 105 patients were followed for a mean of 18.6 months (range 6-89 months). All patients remained in a rigid cervical collar for 8-12 weeks after the laminoplasty. Postoperative cervical plain radiographs were obtained on postoperative day 1, an average of 9.6 weeks postoperatively (range 8-12 weeks) and an average of 10.1 months (range 6-12 months) postoperatively. Thirty-five patients underwent further radiographs >18 months postoperatively. Laminoplasty was performed in 82 patients with progressive cervical spondylotic myelopathy, 4 patients with ossification of the posterior longitudinal ligament, 7 patients for posterior approach to a cervical neoplasm, and 12 patients for early posttraumatic decompression. The canal/vertebral body ratio showed a significant increase from 0.78 to 1.02 (paired t test, p < 0.001). Postoperatively, no incidence of graft dislodgement or segmental instability was diagnosed in any patient. Modified open-door expansive laminoplasty is an effective way of expanding the spinal canal. Its associated low incidence of postoperative instability and kyphotic deformity should make this procedure a desirable substitute for cervical laminectomy under many circumstances.

Cervical Vertebrae↗

PubMed1997

Follow-up computerized tomography (CT) scans in moderate and severe head injuries: correlation with Glasgow Coma Scores (GCS), and complication rate.

BACKGROUND: The wide availability of computerized tomography (CT) scan has popularized its use in initial and follow-up evaluations of head trauma patients. Follow-up CT scans of clinically stable patients, however, may not provide additional information, but could potentially subject the patients to secondary injuries. The authors investigated the correlation between CT scans and Glasgow coma score (GCS), and complication rate during follow-up CT scans in an attempt to dissuade clinicians from obtaining unnecessary follow-up CT scans. METHODS: The medical records of 180 patients with blunt head trauma were retrospectively reviewed. Only patients (117) with moderate and severe head injuries were included in the study. A total of 319 follow-up brain CT's for 94 patients were obtained. RESULTS: The change in CT scans was compared to the GCS the day of the scan. These two variables were found to be positively correlated by Chi-square analysis (chi 2 = 81.2; alpha < 0.001). CPP trend was found also be correlated with CT scan evolution by the Chi-square analysis (alpha < 0.001). When patients had unchanged or improved GCS, 73.1% had improved or the same CT appearance. When patients had a worse GCS, the CT was worse in 77.9%. A 16.9% (54/319) complication rate was documented during the follow-up scans (hemodynamic instability, increased intracranial pressure, desaturation, and agitation). This rate was higher in severe head trauma (GCS 3-8) patients than in moderate head injury (GCS 9-12) patients. Hemodynamic instability was the most common complication, which comprises 42.6% (23/54) of all complications. CONCLUSION: Because of the correlation between the CT scan appearance and the clinical status, as well as the detrimental effect of mobilizing critically ill patients, the authors urge the use of follow-up CT scans only in patients with clinical deterioration unexplained by ICP changes alone.

Blood Pressure↗

PubMed1997

Evaluation of a training program for persons with SCI paraplegia using the Parastep 1 ambulation system: part 1. Ambulation performance and anthropometric measures.

OBJECTIVE: To describe performance parameters and effects on anthropometric measures in spinal cord injured subjects training with the Parastep 1 system. DESIGN: Before-after trial. SETTING: Human spinal cord injury applied research laboratory. PARTICIPANTS: Thirteen men and 3 women with thoracic (T4-T11) motor-complete spinal cord injury: mean age, 28.8yrs; mean duration postinjury, 3.8yrs. INTERVENTION: Thirty-two functional neuromuscular stimulation ambulation training sessions using a commercially available system (Parastep-1). The hybrid system consists of a microprocessor-controlled stimulator and a modified walking frame with finger-operated switches that permit the user to control the stimulation parameters and activate the stepping. OUTCOME MEASURES: Distance walked, time spent standing and walking, pace, circumferential (shoulders, chest, abdomen, waist, hips, upper arm, thigh, and calf) and skinfold (chest, triceps, axilla, subscapular, supraillium, abdomen, and thigh) measurements, body weight, thigh cross-sectional area, and calculated lean tissue. RESULTS: Statistically significant changes in distance, time standing and walking, and pace were found. Increases in thigh and calf girth, thigh cross-sectional area, and calculated lean tissue, as well as a decrease in thigh skinfold measure, were all statistically significant. CONCLUSIONS: The Parastep 1 system enables persons with thoracic-level spinal cord injuries to stand and ambulate short distances but with a high degree of performance variability across individuals. The factors that influence this variability have not been completely identified.

Adult↗

PubMed1997

Evaluation of a training program for persons with SCI paraplegia using the Parastep 1 ambulation system: part 2. Effects on physiological responses to peak arm ergometry.

OBJECTIVE: To examine the task-nonspecific effects of functional neuromuscular stimulation (FNS)-assisted ambulation training on the physiological responses of persons with paraplegia to upper extremity exercise challenge. DESIGN: Before-after trial. SETTING: Human spinal cord injury (SCI) applied research laboratory. PARTICIPANTS: Twelve men and three women with motor- and sensory-complete thoracic-level SCI (T4-T11), mean age 28.2 +/- 6.8yrs (range, 21.1 to 45.2yrs), mean injury duration 3.7 +/- 3.0yrs (range, 7 to 8.8yrs). INTERVENTION: Thirty-two sessions of FNS ambulation training using a commercial six-channel system (Parastep 1). This system is composed of a microprocessor-controlled electrical stimulation unit and a walking frame outfitted with finger switches that allow the user to independently control the system and stimulation parameters. OUTCOME MEASURES: Peak and subpeak physiological responses to arm ergometry testing and upper extremity strength measures, obtained before and after the FNS ambulation training. RESULTS: Statistically significant increases in peak values for time to fatigue, peak power output, and peak VO2 (all p < .001). Heart rate was significantly lower throughout subpeak levels of arm ergometry after the ambulation training (p < .05). Values of upper extremity strength were not significantly altered after training. CONCLUSIONS: FNS ambulation by persons with SCI paraplegia results in task-nonspecific training adaptations. Central cardiovascular adaptations were indicated as the primary source of these beneficial alterations in exercise responses.

Adult↗

PubMed1997

Relationships of oxygen uptake, heart rate, and ratings of perceived exertion in persons with paraplegia during functional neuromuscular stimulation assisted ambulation.

Previous reports have described significant limitations in the daily use of functional neuromuscular stimulation (FNS) ambulation systems by persons with spinal cord injuries (SCI). The potential application of these devices to provide physiological benefits as an exercise modality has prompted a reconsideration of the technology. However, the acute physiological effects related to the use of FNS systems have not been thoroughly examined. The purpose of this study was to investigate the relationships of oxygen consumption (VO2), heart rate (HR), and ratings of perceived exertion (RPE) during FNS ambulation by persons with SCI paraplegia. Eleven persons with thoracic level paraplegia, aged 21.5 to 38.0 years, participated in an incremental FNS ambulation test. Metabolic measures were collected continuously via open circuit spirometry as the subjects performed a series of ambulation passes of progressively increasing pace. At the end of each ambulation pass, HR and RPE measures were collected. The test was terminated when either the subjects judged the effort to be maximal or when the investigators deemed the effort to be maximal based on HR. A strong linear relationship was documented between the VO2 and HR measures of all subjects throughout subpeak levels of FNS ambulation. RPE did not vary proportionally with VO2 until relatively high levels of exercise intensity were reached. This study indicates that HR, but not RPE, is an appropriate indicator of exercise intensity for persons with SCI paraplegia using a FNS ambulation system.

Adult↗

PubMed1997

Bilateral craniotomies for blunt head trauma.

Development of delayed or recurrent intracranial hematomas requiring reexploration or a secondary craniotomy is well known. Patients with bilateral pathology requiring bilateral craniotomies as the initial emergency operative intervention, however, are uncommon. The lack of available literature and the large volume of head trauma seen at our institution prompted us to analyze the retrospective data on blunt head injury requiring bilateral craniotomies. Twenty patients underwent bilateral craniotomies at the University of Miami/Jackson Memorial Medical Center between January 1986 and June 1994. Ages ranged from 18 to 85 years. Mechanism of injury included motor vehicle crash (n = 4), pedestrian hit by automobile (n = 4), assault (n = 8), fall from height (n = 3), and unknown (n = 1). Epidural hematomas, acute subdural hematomas, contusions, and intracerebral hematomas were seen in varying combinations. The preoperative Glasgow Coma Scale (GCS) score ranged from 4 to 14, with a mean of 8.8 (+/-0.82 SE). Sixteen of the 20 patients survived and were discharged from the hospital. The survivors' Rancho Los Amigos Scale score on discharge ranged from 2 to 8, with a mean of 6.1 (+/-0.45 SE). A Fisher's exact test was performed to compare the outcome between the patients with mild (GCS score 13-15) to moderate (GCS score 9-12) head injury and those with severe (GCS score 4-8) head injury. It showed a statistically higher frequency of death in the severe category (p < 0.05). In conclusion, the outcome of patients with bilateral pathology requiring emergency bilateral craniotomy at initial treatment correlated well with their GCS scores at initial presentation.

Adolescent↗

PubMed1997

Modified open-door cervical expansive laminoplasty for spondylotic myelopathy: operative technique, outcome, and predictors for gait improvement.

Twenty-five patients underwent an expansive cervical laminoplasty for nontraumatic cervical spondylosis with myelopathy during the period from June 1990 to November 1994, and all had a minimum of 18 months of follow-up review. The open-door laminoplasty procedure presently reported consisted of the same approach evaluated by Hirabayashi in 1977, except that the authors of this report used three rib allografts to anchor the "open door," rather than spinous process sutures or autologous bone grafts. Posterior foraminotomies and decompression were performed in patients with clinical radiculopathy and radiographic evidence of foraminal stenosis. Preoperatively, gait disturbance was present in all patients. All 25 patients (100%) had long-tract signs on presentation. Nondermatomal upper-extremity symptoms (numbness, tingling, weakness, and pain) were quite common in this group of patients. Bowel, bladder, and/or sexual dysfunction was found in 13 (52%) of 25 patients. Preoperative radiographic studies showed a mean midline anteroposterior diameter spinal canal/vertebral body (SC/VB) ratio of 0.623 and a mean compression ratio (sagittal/lateral diameter ratio x 100%) of 37%. This procedure was quite successful in relieving preoperative symptoms and few complications occurred. Gait disturbance was improved in 21 (84%) of 25 patients and hand numbness and tingling were improved in 13 (87%) of 15 patients. Bowel or bladder function improved in 10 (77%) of 13 patients. Radiculopathy, when present, was alleviated in all four patients after the decompressive procedure. The postoperative SC/VB ratio, as measured by plain lateral radiographs and/or computerized tomography scans, was improved to 0.871, a 38% improvement. In a comparison with the preoperative SC/VB ratio using the two-tailed t-test, alpha was less than 0.001. The compression ratio improved to 63% postoperatively, which yielded an alpha of less than 0.005 according to the two-tailed t-test. Only one postoperative complication, an anterior scalene syndrome, was encountered. Various predictors of surgical outcome based on gait improvement were evaluated. Age greater than 60 years at the time of presentation, duration of symptoms more than 18 months prior to surgery, preoperative bowel or bladder dysfunction, and lower-extremity dysfunction were found to be associated with poorer surgical outcome. Even when these conditions were present, gait improvement was noted in at least 70% of the patients.

Cervical Vertebrae↗

PubMed1997

Progressive posttraumatic myelomalacic myelopathy: treatment with untethering and expansive duraplasty.

Patients with progressive posttraumatic myelomalacic myelopathy (PPMM), or tethered cord syndrome, present with symptoms and signs similar to those observed in case of progressive posttraumatic cystic myelopathy, that is, sensorimotor function deterioration, local and/or radicular pain, increased spasticity, increased autonomic dysreflexia, and sphincter dysfunction. The authors investigated surgical outcomes of untethering combined with expansive duraplasty. Forty patients with PPMM who presented with functional deterioration underwent untethering of the spinal cord and nerve roots with an expansive duraplasty. Meticulous dissections of adhesions on the dorsal and lateral aspects of the spinal cord and nerve roots were performed. Intraoperative ultrasonography was used to detect the presence of a confluent cyst and to assess the success of untethering. After surgery, the patients were treated using a protocol that involved frequent turning for 48 hours and subsequently mobilization. Preoperative magnetic resonance (MR) imaging, with and without administration of a contrast agent, was obtained in all patients, except one patient who underwent immediate and delayed computerized tomography (CT) myelography. The mean follow-up period was 3 years (range 20-57 months) for the 36 patients available for follow-up review. Spinal cord tethering was observed in all patients preoperatively. Trauma was the most common cause of this pathology, accounting for 31 of the 40 cases. Preoperative MR imaging did not demonstrate tumor recurrence in the group of five patients who had undergone an initial operation for tumor excision. The interval between the causative event and the operation was less than 5 years in half of the patients (20 of 40), with the longest interval lasting up to 37 years. Motor function deterioration was the most frequent manifestation; it was present in 31 of 40 patients. Improvements in motor function, autonomic dysreflexia, pain, sphincter dysfunction, and sensory function were found during the most recent follow-up examination in 79%, 75%, 62%, 50%, and 43% of the patients, respectively. Two patients experienced retethering of the spinal cord and one underwent a second operation. Surgical untethering and expansive duraplasty, followed by postoperative position rotation to avoid retethering, provide symptomatic relief for patients with PPMM.

Adolescent↗

PubMed1995

Effects of electrically-stimulated exercise and passive motion on echocardiographically-derived wall motion and cardiodynamic function in tetraplegic persons.

The purposes of the study were (1) to characterize left ventricular wall motion, and the cardiodynamic and metabolic responses during electrical stimulation cycle ergometry (ESCE) exercise in tetraplegic people; (2) to test whether these responses linger into the post-exercise recovery period; and (3) to test whether they differ from those imposed by lower extremity continuous passive motion (CPM). Subjects were six tetraplegic males aged 25.8 +/- 3.1 (mean +/- SD) years with spinal cord injuries of 6.7 +/- 3.5 years' duration at the C5 and C6 levels (Frankel classifications A and B). On randomized non-consecutive days, subjects underwent either 30 min of steady-state exercise using transcutaneous electrically-stimulated contractions of bilateral quadriceps, hamstring, and gluteus muscle groups, or 30 min of continuous passive motion at 50 rpm. Data were taken at rest, min 15 and 30 of treatment, and min 5, 15, and 30 post-treatment. Stroke volume (SV) was measured echocardiographically as the product of the left ventricular outflow tract area and the integrated area under the left ventricular outflow tract flow-velocity curve acquired by doppler ultrasound. This value was multiplied by heart rate (HR) to determine the cardiac output (CO). Oxygen consumption (VO2) was monitored spirometrically, with arteriovenous oxygen difference (a-vO2DIFF) computed algebraically. Data were analyzed using repeated measures within-subjects design anaysis of variance, with significance accepted at the 0.05 level. Results showed five subjects had small hyperkinetic ventricles at rest that became more dynamic during ESCE than CPM. Though no systolic dysfunction was noted, all but one subject exhibited some degree of septal hypokinesis at rest and during exercise, possibly indicative of left ventricular noncompliance. Significant effects of condition (ESCE vs CPM), trial (measurement time point), and their interaction, were observed for CO (P < 0.05, 0.01, and 0.0001, respectively), HR (P < 0.0001, 0.05 and 0.005, respectively), and VO2 (P < 0.001, 0.05 and 0.005, respectively). A significant trial and condition by trial interaction was found for a-vO2DIFF (P < 0.05 and 0.0001, respectively). No effects for condition, trial or their interaction were found for SV or BPDIAS. Electrical stimulation cycle ergometry-treated subjects achieved peak VO2 of 712 +/- 300 ml min-1, 2.63 times baseline, with 56% elevation of a-vO2DIFF. Cardiac output increased from 3.5 +/- 1.51 min-1 to 6.0 +/- 2.11 min-1, an elevation solely attributable to a 57% increase in HR. Thus, both CO and a-vO2DIFF accounted for elevated VO2 during ESCE.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1995

Dorsal spinal venous occlusion in the rat.

Occlusion of the major components of the spinal venous system is usually associated with spinal arteriovenous malformations or systemic thrombophlebitis. Although spinal venous system dysfunction has been implicated in compressive cord syndromes, myelopathies from decompression sickness, and spinal cord trauma, its pathophysiology remains unclear. To characterize disorders associated with spinal venous occlusion, we developed a model in the rat produced by focally coagulating the dorsal spinal vein transdurally at the T7 and T10 vertebral levels. Following such occlusion, venous stasis, sludging and perivascular hemorrhages in the small venous branches were observed. By 1 week postocclusion, animals developed hindlimb paralysis from which they partially recovered over time. Histologic examination in the acute phase disclosed tissue necrosis, edema, and hemorrhages predominantly in the dorsal aspect of the spinal cord. This was gradually replaced by an intense macrophagic infiltration and the partial formation of a cystic cavity by 1 month. These findings indicate that dorsal spinal vein occlusion in the rat causes significant neurologic and pathologic alterations. We conclude that this procedure produces a relevant animal model for the study of the pathophysiology of spinal venous occlusion, and it allows the characterization of its effects on spinal cord blood flow, the blood-spinal cord barrier, and the development of edema independent of cord compression. Our findings in this model provide an insight into one of the mechanisms of injury extension in spinal cord trauma and other disorders associated with spinal venous dysfunction.

Animals↗

PubMed1995

Replacing residents with midlevel practitioners: a New York City-area analysis.

Reducing the number of residency positions in U.S. teaching hospitals poses special problems for New York City-area hospitals, which rely heavily on residents to deliver patient care services. This study analyzes the costs of replacing residents with midlevel practitioners under proposals considered in 1994 by Congress to limit the number of first-year training positions and alter the configuration of primary care physicians and specialists produced. The study found that, depending on the replacement strategy used, the proposals could require New York City-area hospitals to hire thousands of midlevel practitioners and other staff, costing a minimum of $242 million annually, to cover patient care services.

Allied Health Personnel↗

PubMed1994

Transthoracic disc excision and fusion for herniated thoracic discs.

Transthoracic discectomy and fusion were performed on 19 patients for a central or central-lateral herniated thoracic disc. At initial visit, 14 patients had evidence of myelopathy, 5 had bowel or bladder dysfunction, and 13 had pain. Previous laminectomy in three patients compromised the result of later anterior decompression. Coexistent multiple sclerosis was diagnosed in two patients, who had an atypical postoperative course. The overall results of transthoracic discectomy and fusion in patients without prior laminectomy or coexistent multiple sclerosis were excellent in six, good in six, fair in one, and poor in one, demonstrating that it is a safe and effective procedure.

Diskectomy↗