The systolic pressure variation (SPV), which is the difference between the maximal and minimal systolic blood pressure (SP) during one ventilatory cycle, was studied in ten patients during posterior spine fusion. To minimize the blood loss, deliberate hypotension to a mean blood pressure of 50 mmHg was introduced by a continuous infusion of sodium nitroprusside. SPV was further divided into two components, delta up and delta down, using SP during a short apnea as a reference point. All hemodynamic parameters were measured at the beginning of anesthesia, 15 minutes after induction of hypotension, before cessation of nitroprusside infusion, and 15 minutes after the end of the hypotensive period. During the hypotensive period (166 +/- 53 minutes), cardiac output (CO) decreased significantly from 4.83 +/- 1.36 L/min to 3.86 +/- 1.07 L/min (p less than 0.05). Heart rate (HR), central venous pressure (CVP), and pulmonary capillary wedge pressure (PCWP) did not change during this period and bore no correlation to the changes in CO. The only variables that changed during the hypotensive period, in addition to CO, were SPV (from 13.1 +/- 4.9 mmHg to 16.9 +/- 5.1 mmHg, p less than 0.02), and delta down (from 6.0 +/- 3.8 mmHg to 9.9 +/- 6.3 mmHg, p less than 0.05). The delta down segment was the only hemodynamic variable whose changes during the hypotensive period showed a significant (p less than 0.018) correlation with the changes in CO. delta down reflects the degree of decrease in left ventricular stroke output in response to a positive pressure breath, and thus is a sensitive indicator of preload.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

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The efficacy of amitriptyline and acetaminophen in the management of acute low back pain.

Thirty-nine patients with acute low back pain were treated with amitriptyline (150 mg/d) or acetaminophen (2,000 mg/d) in a controlled double-blind design for 5 weeks. Both groups revealed mild depression, normal coping, and increased anxiety at the beginning, with significant improvement in anxiety state and pain at the end of treatment. A repeated measures analysis of variance demonstrated that amitriptyline was more effective than acetaminophen in reducing pain intensity from the second week of treatment. Age and depression were the only significant pretreatment predictors of posttreatment pain. The study evaluates the significance of these findings.

Acetaminophen↗

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Low-back pain and sciatica following total hip replacement: a report of two cases.

Two cases of low-back pain and sciatica following total hip replacement are reported. Both patients were operated upon and after lumbar decompression were free of pain. A theory is presented to suggest that the lengthening of the limb after total hip replacement puts excess tension on the spinal nerves and, in conjunction with preexisting degenerative disc disease, will precipitate low-back pain and sciatica.

Aged↗

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Platelet aggregation abnormalities in idiopathic scoliosis.

Platelet aggregation studies were performed in 22 adolescent girls with idiopathic scoliosis. Impaired ADP-induced platelet aggregation was found in washed platelets of the 22 patients with idiopathic scoliosis when compared with the controls (76.5% of control values; p less than 0.01). Furthermore, platelets from patients with progressive curves showed a greater degree of abnormality than platelets from those with nonprogressive curves, e.g., 57.6 +/- 22% of control values (p less than 0.001). No significant differences in aggregation could be detected when platelets were aggregated with the ionophore A-23187 in either the absence or the presence of calcium. Platelet aggregation studies in patients with other spinal deformities did not differ from the healthy controls. Because platelets share similar contractile proteins as muscles, the present study suggests that a muscle disorder may play an important pathogenic role in idiopathic scoliosis.

Adenosine Diphosphate↗

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Cervical instability in an achondroplastic infant.

Cervical spine instability is a rare finding in achondroplasia. We present the previously unreported case of C2-C3 subluxation producing progressive quadriparesis in an achondroplastic infant. Operative treatment with appropriate fusion was performed, and an excellent result was obtained.

Achondroplasia↗

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The effect of protein malnutrition and nutritional support on the mechanical properties of fracture healing in the injured rat.

We investigated the effect of different nutritional regimens on fracture healing in the injured rat model. Four groups, each consisting of 12 male rats (307 +/- 16 g), were subjected to anesthesia, laparotomy (injury), and tibial osteotomy with internal fixation. Group I received 23% protein, group II received 23% protein and high caloric feed, group III received 5% protein, and group IV received 38% protein. After 8 weeks, calluses were x-rayed and the tibia was removed, fixed in a special block of methyl-metacrylate, and tested at tension up to failure in a mechanical testing apparatus. The distraction force at failure was measured, and callus stiffness and energy absorbed to failure were calculated. The low protein diet resulted in significantly lower tensile strength and stiffness of calluses compared to the other three dietary regimens, this despite adequate caloric intake. In addition, the low protein diet resulted in a callus with "rubbery" mechanical properties compared to the "rigid" calluses of the other three groups. The high protein diet did not result in any significant improvement in fracture healing. These results gain clinical significance in the face of a high incidence of protein calorie malnutrition in injured orthopedic surgery patients.

Analysis of Variance↗

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Peripheral arterial embolectomy in the aged.

A series of 65 geriatric patients, operated upon for 76 peripheral arterial embolic events, is presented. The underlying condition was rheumatic heart disease in 8 and arteriosclerotic in 57. No patient was denied surgery unless widespread irreversible ischemia of the limb was present. Limb salvage was accomplished in 35 patients (54%). It was influenced by age, the underlying disease and time elapsed until resumption of circulation to the limb. The mortality rate experienced in this series was very high. 31 patients (48%) died postoperatively, mainly from cardiorespiratory failure. Death was related to the severity of the patients condition before surgery. 29 out of the 34 surviving patients were discharged with a viable limb. The high death rate observed is discussed.

Age Factors↗

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Cauda equina syndrome presenting as a herniated lumbar disk.

Cauda Equina Compression (CEC) is a clinical syndrome consisting of low back pain, bilateral sciatica, saddle anesthesia, bilateral lower extremity weakness, and even frank paraplegia with bowel and bladder incontinence. At the onset of CEC, the clinical picture may resemble typical intervertebral disk disease with low back pain and unilateral sciatica. The back pain is severe, overshadowing the leg pain, and should alert the physician to the periodic evaluation of the patient and evidence of a progressive neurologic deficit. Early discovery of CEC is necessary if neurologic recovery is to be expected from decompressive laminectomy.

Aged↗

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Induction of osteoarthrosis in the rabbit knee joint: biochemical studies on the articular cartilage.

Measurements of uptake in vivo of 3H-proline into 3H-hydroxyproline demonstrate that cartilage surfaces in rabbit knees with surgically induced osteoarthrosis (up to 3 months after operation) incorporated 2 to 5 times more activity into collagen than cartilage of control knees. The high uptake indicates that collagen synthesis was stimulated severalfold. In the lateral compartment of the experimental knee, which did not develop lesions, the 3H-proline metabolism was also stimulated, but this reaction subsided after 3 months. In the medial compartment, where the focal lesions developed, the stimulation continued. The newly made collagen was predominantly Type II; no evidence was found for a significant production of Type I collagen, even in the focal lesion on the medial tibial plateau more than a year after surgery. By radiochemical labelling with 3H-glucosamine,, an increase in the ratio of 3H-galactosamine to 3H-glucosamine was detected in all cartilage surfaces at intervals of 2-5 weeks after surgery. The increase was associated with the transient synovitis before lesions appeared, but not later. The observations suggest that synovitis and mechanical stresses are both important in inducing osteoarthrotic lesions.

Animals↗

PubMedDate not supplied

Degenerative lumbar spinal stenosis.

Advanced degenerative multilevel disk disease of the lumbar spine with resultant spinal stenosis may lead to neurogenic intermittent claudication, which closely mimics claudication due to aortofemoral disease. Narrowing of the lumbar spinal canal, the lateral recesses and intervertebral foramina secondary to degenerative disk disease is brought about by hypertrophy of laminae, facet joints and ligamentum flavum, descent of the pedicles, posterior bony ridging and occasional disk herniation. The symptoms are elicited by lumbar lordosis and are relieved by lumbar flexion. Five patients with degenerative lumbar stenosis are presented. Decompressive laminectomy yields satisfying results, regardless of the advanced age of some of the patients, and allows normal ambulation.

Aged↗