Neural compression due to osteochondral fragments. A report of two cases and review of the literature.
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Adult↗
Biomedical subjects
F T Wetzel
Publications and source records attributed to F T Wetzel.
Chronic benign cervical pain syndromes. Surgical considerations.
The results of surgical intervention for chronic benign pain syndromes are generally poor. In this review, pertinent ablative and modulatory techniques are reviewed, with specific reference to their utility for benign pain syndromes. With the possible exception of facet rhizotomy, the ablative modalities have little role in the management of benign pain syndromes. The more extensive techniques of cordotomy, dorsal root entry zone lesioning, ganglionectomy, and rhizotomy, have erratic results and high rates of complication. No long-term studies exist to support the use of facet rhizotomy. It is minimally invasive, however, and has little morbidity. In patients with benign refractory posterior column pain, facet rhizotomy may be worth consideration. Modulatory devices may have a role in benign pain syndromes. While the use of indwelling epidural catheters remains investigational, dorsal column stimulation has been widely studied. In representative reports, significant pain relief has been observed in up to 60% of patients (mean follow-up of two years). In the carefully selected patient, this may represent a valuable therapeutic adjunct.
Cervical Vertebrae↗
The treatment of chronic extremity pain in failed lumbar surgery. The role of lumbar sympathectomy.
Persistent lower extremity pain after unsuccessful lumbar surgery continues to be a disabling condition. The results of deafferentation procedures for radiculopathy have been disappointing. Hence, the prospect of isolating a potentially reversible component of extremity pain is quite attractive. Given the frequency with which vasomotor complaints occur in this setting, the occurrence of autonomic dysfunction seems quite plausible. Autonomic dysfunction was investigated in 17 patients who had undergone previous lumbar surgery and had chronic limb pain. Patients underwent a preblockade thermogram, sympathetic blockade, and postblockade thermograms. All patients reported substantial relief after blockade, and all underwent retroperitoneal sympathectomy. All patients were followed for at least 2 years. The clinical results were disappointing, with only one patient reporting substantial relief. Although the results of thermography initially seemed to correlate with clinical outcome, further follow-up failed to yield any correlation. Additionally, no specific combination of response to blockade or thermogram was predictive of the clinical success after sympathectomy. Now, lumbar sympathectomy is not recommended in the setting of chronic radiculopathy and persistent extremity pain.
Female↗
The failed posterior lumbar interbody fusion.
The problems presented by unsuccessful posterior lumbar interbody fusion (PLIF) have not been addressed. The cases of 12 patients who presented with failed PLIF were reviewed. Five patients were male and seven female (age range, 24-50 years; mean age, 40 years). All patients underwent at least one PLIF; many had undergone other procedures. A total of 37 procedures had been performed on the 12 patients. Chronic radiculopathy was present in all patients, as detected with electromyographic or nerve conduction velocity examination. At the time of reconstructive surgery, in the 11 patients in whom the canal was explored, all had extensive epidural fibrosis. Nine of the 12 patients had pseudarthrosis of the previous PLIF. Four patients had evidence of motion segment dysfunction at nearby levels: two had positive discograms adjacent to the PLIFs; one developed a facet syndrome at L5-S1, caudal to an L4-5 PLIF; and one demonstrated frank segmental instability at L2-3, cranial to a previous PLIF at L3-4. Twelve patients underwent a total of 22 procedures after referral. Eleven patients initially underwent decompression and fusion, and one patient underwent a sympathectomy. Seven patients underwent an additional 10 procedures, including repeat decompression, repair of pseudarthrosis, and implantation of an epidural analgesic pump system. After all surgical treatment, five patients rated their pain as improved. Seven patients were thought to have a solid fusion. The presence of a solid fusion did not correlate with satisfactory relief of pain (chi-square). Continued extremity pain was the predominant complaint of all the patients. Two shortcomings of the PLIF were evident.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Biomechanics of the rabbit cervical spine as a function of component transection.
The rabbit cervical spine in the form of the functional spinal unit was tested in a manner analogous to that used to study human functional spinal units. Anatomies and biomechanical similarities and differences with the human were demonstrated. The rabbit cervical spine failed abruptly after a well-defined series of anterior or posterior segmental injuries. However, up to the failure point, the rabbit cervical spine exhibited an increased range of motion after each segmental injury. The results of this study were used to develop an in vivo model for the study of spinal injury in subsequent projects.
Animals↗
Temporal biomechanics of posterior cervical spine injuries in vivo in a rabbit model.
There are numerous clinical and biomechanical criteria for determination of acute spinal instability. No data, however, exist on the biomechanical behavior of the injured, untreated spine during the healing period. Using a rabbit model, this study was designed to quantify changes in the mechanical properties of the injured spine over time. Sixteen rabbits were assigned to four injury groups: Injury 1 (C4-5 supra/intraspinous ligament transection), Injury 2 (C4 laminectomy), or Injury 3 (C4 laminectomy, plus bilateral facet capsular ligament transection). The fourth injury group was Sham (posterior exposure of C4-5, no spinal injury). Preinjury range of motion was determined by standardized flexion-extension radiographs on all animals. Postinjury flexion-extension radiographs were taken at 4, 8, and 12 weeks. At the end of 12 weeks, animals were killed. Mean range of motion at C4-5 for all injury groups decreased from preinjury values. The greatest decrease was for the most severe injury. At 8 weeks, the range of motion for this injury was less than half of the preinjury level and increased to 62% of the preinjury level at 12 weeks.
Animals↗
Grisel's syndrome.
Grisel's syndrome is a unilateral or bilateral subluxation of C1 on C2, associated with an infectious condition in the head or neck. Anatomic studies have demonstrated the existence of a periodontoidal vascular plexus that drains the posterior superior pharyngeal region. No lymph nodes are present in this plexus, so septic exudates may be freely transferred from the pharynx to the C1-C2 articulation. The resulting synovial and vascular engorgements may cause mechanical and chemical damage to the transverse and facet capsular ligaments leading to subluxation. The primary treatment of Grisel's syndrome is medical: the underlying infectious organism must be isolated and appropriate antibiotics prescribed. The subluxation is reduced in halter or skeletal traction. The authors use the classification scheme of rotary subluxation proposed by Fielding, so that treatment appropriate to the specific type of subluxation is used. Based on biomechanical data predicting articular instability and canal compromise proportional to the extent of ligamentous injury, the following specific forms of immobilization are recommended to ensure ligamentous healing: Fielding Type I (transverse ligament intact and bilateral facet capsular injury) soft collar; Type II (transverse ligament and unilateral facet capsular injury) Philadelphia collar or SOMI brace; and Type III (transverse ligament and bilateral facet capsular ligament injury) halo. Following six to eight weeks of immobilization, stability is assessed by the study of flexion-extension roentgenograms. Should residual instability be demonstrated, arthrodesis is indicated.
Adolescent↗
Upper cervical spine involvement in rheumatoid arthritis.
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Arthritis, Rheumatoid↗
Poor growth prior to early childhood: decreased health and life-span in the adult.
Previous studies in animal populations have shown that stunted neural and thymolymphatic growth early in development may result in permanently impaired neural and immune function, decreased body growth, vertebral wedging, and decreased life-span. In the human adult, small vertebral neural canal (VNC) diameters may reflect early stunted neural and immune development and impaired function that leads to decreased health (inferred by greater vertebral wedging) and life-span in the adult. VNC, which complete their growth by early childhood (age 4), are markers of early development in adults. On the other hand, features following general body growth, such as height, weight (represented here by vertebral body height) continues to grow until young adulthood. They are less reliable, because they readily experience catch-up growth (even in chronically stressed populations) and, unlike VNC, may mask poor early growth. To test associations between early growth and adult health and life-span in humans, we measured 2,060 VNC, vertebral heights, vertebral wedging, nerve-root tunnel lengths, severity of vertebral osteophytosis, and ages at death in 90 adult (aged 15-55 years) prehistoric skeletons (950-1300 A.D.). Tibial lengths were also measured in a subsample (n = 30). Multivariate, bivariate, and nonparametric analyses showed that small VNC are significantly associated with greater vertebral wedging and decreased life-span (P less than 0.05-0.00001). VNC are independent of vertebral body heights and tibial lengths (general body growth). VNC, but not statural components, are useful in predicting adult health, presumably because they reflect neural and immune development and do not readily experience catch-up growth. Thus, longitudinal retrospective measures of early growth and adult health were systematically linked within individuals regardless of confounding factors operating over the 350-year time period. Since this research was completed, this model has repeatedly been independently confirmed in four living urban industrial populations. Longitudinal retrospective analysis was employed together with direct measures of VNC, neural and immune function. Together these results suggested that it may be essential to improve growth prior to early childhood in order to maximize adult health and life-span.
Adolescent↗
Can infant malnutrition cause adult vertebral stenosis?
Does infant malnutrition produce smaller adult spinal canals? Lumbar and thoracic vertebrae (n X 1073), from a prehistoric American Indian population (15-55 yrs of age), were measured for anteroposterior (AP) and transverse (TR) vertebral canal sizes, nerve root tunnel (intervertebral foramen) widths (NRT), vertebral heights (VH), vertebral osteophytosis (VO), and tibial lengths. They underwent a dietary change from hunting-gathering, protein rich (PR), to maize agriculture, protein deficient (PD), between 950 and 1300 A.D. Multivariate analyses controlled for age, sex, culture, NRT, VH, VO, and wedging. Canal size was significantly smaller in the PD. AP diameters were generally and highly correlated with NRT, and thus both spinal stenosis and sciatica may have a developmental basis. Canal size was independent of statural components. Consequently, canal size is a most powerful tool in assessing the presence infant malnutrition. Moreover, perhaps the association between canal size and low-back pain (LBP) found in living populations has been underestimated, and this component of LBP is preventable.
Adult↗
Hormonal control of male reproductive behavior in the lizard, Anolis carolinensis: role of testosterone, dihydrotestosterone, and estradiol.
The androgen aromatization hypothesis was examined in the male lizard, Anolis carolinensis. After castration, sc silastic implants of testosterone (T) restored both challenge and courtship behavior, while dihydrotestosterone (DHT) or 17beta-estradiol (E) had no effect on male behaviors. Both T and DHT, but not E, stimulated hypertrophy and colloid production by the renal sex segment, a secondary sexual characteristic of male lizards. In two separate studies, castrates received DHT in combination with E. In each replicate, half of the castrates responded with increases in courtship behavior after hormone treatment. Epithelial cell height of the sex segment of all DHT and E-treated castrates was comparable to T- or DHT-treated castrates, but colloid production was not stimulated. These experiments indicate that in this species, treatment with T stimulates both sexual behavior and secondary sex character development, whereas treatment with E alone is without effect centrally or peripherally.
Animals↗