Foraminal stenosis of the lumbar spine: a review of 65 surgical cases

This study provides clinical and radiographic information and characteristics that may best define the presence of significant lumbar foraminal stenosis and reports on the outcome of surgical intervention. Although anatomy of the lumbar intervertebral foramen (including static and dynamic pathologic compression of the exiting nerve root) has been described, few studies have focused on the clinical and radiographic features of foraminal stenosis requiring surgical intervention. We retrospectively studied 65 patients with lumbar foraminal stenosis for presenting clinical and radiographic features and intraoperative findings. Symptoms included leg and back pain (100%), paresthesias (45%), and subjective weakness (31%). Examination revealed lumbar tenderness (71%), limited lumbar extension (57%), focal motor weakness (48%), and positive tension signs (42%). The L5 nerve root was most often involved (75%). Almost 50% of patients had already undergone spinal decompression surgery. Surgical procedures included laminectomy and foraminotomy (52 patients) and laminotomy and foraminotomy (23 patients). A concomitant arthrodesis was performed in 63 patients. There were 29 excellent, 25 good, 6 fair, and 5 poor results based on a modified outcome scale at 32.5-month follow-up. Findings suggest that foraminal stenosis is a frequent cause of persistent symptoms after surgery, is most common at the lumbosacral junction, is best identified on parasagittal magnetic resonance images or on images reconstructed with computed tomography, and may be static or dynamic in etiology.

A prospective comparison of the standard and reverse robinson cervical grafting techniques: radiographic and clinical analyses

The authors performed a prospective study of 63 patients with cervical radiculopathy treated with Robinson anterior cervical discectomy and fusion and compared the traditional or standard and reverse graft techniques. Modifications of the standard Robinson grafting techniques have been proposed. The reverse graft technique has theoretical advantages, including limiting the deleterious effects of graft extrusion and maintaining rigid middle column support. A radiographic evaluation and an assessment of clinical outcome based on the criteria of Odom were performed prospectively for as long as 1 year after surgery. Thirty-one patients were treated with the standard grafting technique and 32 with the reverse graft orientation. The radiographic evaluation showed no significant differences between the two techniques with regard to sagittal alignment and disk heights. The overall fusion grade was higher in the reverse graft technique (p < 0.05). There were 93% and 96% good to excellent results in the standard graft and reverse graft groups, respectively. The authors report no significant differences associated with the standard or reverse anterior cervical grafting techniques in terms of radiographic alignment or disk height loss over time or at early clinical outcome. However, improved fusion grade was noted with the reverse graft technique, which may be related to end plate and intervertebral space preparation. The reverse grafting technique is an acceptable alternative to the standard graft orientation.

Neck pain secondary to radiculopathy of the fourth cervical root: an analysis of 12 surgically treated patients

Neck pain can originate from any number of factors. Perhaps the most difficult symptom complex to resolve is axial neck pain arising from upper cervical nerve root compression. The purpose of this study is to report the results of surgical intervention in a series of patients with neck pain from C4 radiculopathy. Twelve consecutive patients who were diagnosed with C4 radiculopathy were retrospectively reviewed (follow-up, 22+/-16.3 months). Patients underwent either anterior cervical discectomy and fusion or posterior laminoforaminotomy at the C3-C4 segment. The results show that a good to excellent clinical result can be achieved in most patients (92% in our series). The importance of identifying patients with C4 radiculopathy lies in the fact that surgery can alter the natural history of neck pain secondary to upper cervical root radiculopathy, unlike axial neck pain from degenerative disk disease.

Prospective comparison of the effect of direct current electrical stimulation and pulsed electromagnetic fields on instrumented posterolateral lumbar arthrodesis

The purpose of this prospective study was to compare the effect of adjunctive direct current (DC) electrical stimulation and pulsed electromagnetic field therapy (PEMF) on augmentation of instrumented lumbar fusion. Sixty-one patients undergoing lumbar spine fusion were enrolled in the study and randomized to one of three treatment protocols: 1) adjunctive PEMF group (n = 22) fitted with Spinal-Stim model 8212(AME) within 30 days of surgery; 2) DC group (n = 17) had a SpF-2T stimulator(EBI) implanted at the time of surgery; or 3) control group (n = 22). The fusion mass bone mineral density (BMD) assessment was performed on 3-month and 1-year radiographs for each patient. Lateral flexion-extension and anteroposterior radiographs were evaluated at 1 year to determine the presence of fusion. Clinical outcome patient analyses were performed at 1 year. At 1-year follow-up, radiographic fusion and fusion mass bone density were not significantly different among the groups. In the nonstimulated group, there were 43% excellent, 43% good, and 14% fair results. In the PEMF group, there were 35% excellent, 50% good, 10% fair, and 5% poor results. In the DC group, there were 32% excellent, 37% good, and 31% fair results. The results of the current study suggest that electrical stimulation does not significantly enhance fusion rate in instrumented lumbar arthrodesis, although we observed a statistically insignificant trend toward increased fusion mass BMD in the electrically stimulated groups. The significance of increased BMD remains unknown.

Spine update. Lumbar foraminal stenosis

Lumbar foraminal stenosis is an important pathologic entity to identify in the patient being treated for radicular symptoms. This update reviews the anatomy, clinical presentation, neuroradiographic evaluation, and treatment of pathology located in the intervertebral foramen. Patients with significant leg pain refractory to conservative treatment and concordance between the demonstrated area of stenosis and radicular symptoms and signs are candidates for the decompressive procedures discussed. The role of arthrodesis and spinal instrumentation in the management of foraminal stenosis also is addressed.

Variation in the posterior vertebral contour line at the level of C-2 on lateral cervical roentgenograms: a method for odontoid fracture detection

As an aid to the assessment of alignment and lordosis, four contour lines can be drawn on the lateral radiograph of the cervical spine. One of these contour lines is the posterior vertebral contour line, in which a smooth, gentle curve, convex anteriorly, is formed by a line drawn along the posterior margins of the cervical vertebral bodies. It is unknown whether discontinuity in the posterior contour line at this level represents a pathologic process of the odontoid. We analyzed the posterior cortex of C-2 and the odontoid in 500 lateral cervical spine radiographs to determine the amount of step-off (deviation from the posterior contour line) seen in normal lateral cervical roentgenograms. Only 15% (n = 75) showed any step-off; none exceeded 3 mm. We recommend that patients presenting with a history of cervical spine trauma who have a step-off at the posterior contour line at the odontoid/C-2 level of > or =3 mm should have fine-cut tomography or multiplanar computed tomography scanning to further assess the odontoid process and rule out fracture.

Metastatic disease of the cervical spine. A review

The treatment of cervical metastatic disease requires a multidisciplinary team approach to evaluation and management and demands consideration of multiple factors before a regimen is accepted. The patient's overall functioning and medical status, life expectancy, history of treatment, tumor type, and location within the cervical spine and individual vertebrae all must be evaluated carefully. The majority of lesions will be amenable to nonoperative aggressive modalities aimed at shrinking tumor size and halting growth. Surgical intervention is limited to specific indications, including spinal instability, progressive neurologic deterioration from bony collapse and compression, intractable pain, and failure of conservative means of treatment.

A prospective study of proximal femur bone mass following cemented and uncemented hip arthroplasty

Cross-sectional studies have demonstrated significant decreases in bone mass in femoral cortical bone adjacent to prostheses. Thirty-six patients who had undergone 31 cemented and 9 uncemented primary total hip arthroplasties (THA) were prospectively studied to define further the natural history of this femoral cortical bone loss. Dual-energy X-ray absorptiometry (DXA) was employed to quantify bone mineral density (BMD) changes in four subregions around the femoral prostheses. Femoral BMD loss (average 12.3%) was observed in the three proximal subregions 2 months postoperatively. This loss increased to 21.2% by 6 months postoperatively, and by 2 years postoperatively it averaged 25.5% in the same three subregions. There were no significant BMD changes in the subregion distal to the prosthesis tip or in the contralateral hip. Subgroups were compared based on prosthesis size and cement use. Statistically significant differences in BMD loss were observed between the large cemented cobalt chrome prosthesis group (n = 8) and the large uncemented titanium prosthesis group (n = 8). These differences were only present in the most proximal medial subregion where the large cemented groups had twice the bone loss in this area as compared with the large uncemented group. The data indicate that bone loss occurs adjacent to femoral prosthesis within 2 months of surgery and that DXA is a useful technique to quantify prospectively femoral cortical bone loss following THA.

Complete vertebral fracture/dislocation of the cervical spine with minimal neurologic deficit

Cervical spine fracture/dislocations without neurologic compromise are rare. We report the case of a complete fracture/dislocation from C-5 to C-6 with neurologic sparing and discuss the biomechanical pathogenesis and treatment of this injury.

Responsiveness of gene expression markers of osteoblastic and osteoclastic activity to calcitonin in the appendicular and axial skeleton of the rat in vivo

We have previously shown that calcitonin (CT), an inhibitor of bone resorption, increases vertebral, but not femoral bone density in the rat. To address the physiologic responses associated with these effects on bone mineral density (BMD), we assessed mRNA transcripts reflecting activities of osteoblasts (type I collagen, osteocalcin, osteopontin, and alkaline phosphatase), osteoclasts [tartrate-resistant acid phosphatase (TRAP)], and cell proliferation (histone H4) in the spine and femur of these rats. CT increased spine BMD while increasing type I collagen and decreasing TRAP and histone mRNAs. In the femur, where CT had no effect on BMD, it decreased type I collagen and histone H4 mRNA but did not affect TRAP. CT had no effect on the gene expression of osteocalcin, osteopontin, or alkaline phosphatase at either site. The results indicate that selective alterations in gene expression, as reflected by steady state mRNA levels, are consistent with the changes observed by BMD measurement, and can more clearly define the specific contribution from osteoblast and osteoclast activity. This study demonstrates a heterogeneity in response of the axial and appendicular skeleton to CT, reflected by alterations in gene expression that provide a basis for understanding the observed BMD responses to various pharmacologic interventions.

Late vascular complication with anterior cervical discectomy and fusion

STUDY DESIGN

The authors report a patient with delayed inferior thyroid artery pseudoaneurysm after uneventful anterior cervical discectomy and fusion.

METHODS

The Smith-Robinson approach to the anterior cervical spine is a commonly used and relatively safe surgical approach for cervical disc disease.

RESULTS

This case is unusual in two respects: 1) the vascular complication occurred 9 days postoperatively; and 2) the inferior thyroid artery was embolized without the need for immediate exploration and surgical ligation.

CONCLUSION

The patient was successfully managed with therapeutic embolization.

Etidronate inhibits the thyroid hormone-induced bone loss in rats assessed by bone mineral density and messenger ribonucleic acid markers of osteoblast and osteoclast function

TSH-suppressive doses of thyroid hormone are associated with bone loss. We have previously reported that L-T4 decreases femoral, but not vertebral bone mineral density (BMD) in rats. As bisphosphonates are able to decrease bone resorption, especially in high bone turnover states, we investigated the potential effects of etidronate disodium (EHDP) on L-T4-induced bone loss in the rat model by assessing BMD and gene expression of osteoblast (osteocalcin, osteopontin, type I collagen, and alkaline phosphatase), osteoclast (tartrate-resistant acid phosphatase), and cell growth (histone) markers in the skeleton. L-T4 administered for 20 days decreased BMD in the femur, but had no effect on the lumbar spine. EHDP alone had no effect on femoral or vertebral BMD, but did prevent the L-T4-induced bone loss in the femur. L-T4 increased mRNA levels of alkaline phosphatase, tartrate-resistant acid phosphatase, and histone H4 in the femur, but not in the vertebrae. EHDP, which alone had no effect on gene expression in the femur or vertebrae, inhibited the effect of L-T4 on mRNA markers in the femur. The results demonstrate that EHDP can prevent the L-T4-induced decrease in femoral BMD in rats that is associated with the prevention of changes in mRNA markers of osteoclast and osteoblast function. EHDP and other bisphosphonate compounds may be useful in the prevention of thyroid hormone-induced bone loss in humans.

1 alpha,25-dihydroxyvitamin D3-induced changes in intracellular pH in osteoblast-like cells modulate gene expression

1 alpha,25-Dihydroxyvitamin D3 exerts rapid nongenomic effects on rat osteoblast-like cells independent of the classic nuclear receptor. These effects include changes in phospholipid metabolism and cell calcium. Intracellular calcium itself has been proposed to regulate intracellular pH in osteoblast cell lines. The purpose of this study was to determine the effect of 1 alpha,25-dihydroxyvitamin D3 on intracellular pH, the relationship of changes in calcium to changes in pH, and the role of pH changes in genomic activation. 1 alpha,25-Dihydroxyvitamin D3 increased intracellular pH within 10 min in rat osteoblast-like cells, an effect that was inhibited by removal of extracellular sodium and by the biologically inactive epimer 1 beta,25-dihydroxyvitamin D3. The hormone increased intracellular calcium in Quin 2 loaded cells in the presence and absence of extracellular sodium. The 1 alpha,25-dihydroxyvitamin D3-induced increments in osteocalcin and osteopontin mRNA levels were abolished in sodium-free medium. The results indicate that 1 alpha,25-dihydroxyvitamin D3-induced increments in cellular calcium precede cell alkalinization and that these changes in intracellular pH may modulate steady-state mRNA levels of genes induced by vitamin D.

Effect of gallium nitrate in vitro and in normal rats

Gallium nitrate (GN) is an inhibitor of bone resorption and thereby may result in a change in coupled bone formation. In the present investigation the effects of GN on bone formation were studied in the rat osteosarcoma (ROS) 17/2.8 cell line and normal diploid rat osteoblasts (ROB) in vitro and the femur of rats treated in vivo, measuring mRNA levels for two osteoblast parameters, type I collagen, a marker of matrix formation, and osteocalcin, a bone specific protein and also histone H4, a marker of cell proliferation. GN, at 50 microM for 3 h, increased type I collagen mRNA levels by 132% in ROS 17/2.8 cells and by 122% in proliferating ROB cells. Osteocalcin (OC) mRNA levels were decreased by 61% in ROS 17/2.8 cells and by 97% in differentiated ROB cells. These changes occurred in the absence of any effects on cell proliferation. Seventy-day-old female rats were then treated with GN, 0.5 mg/kg/day, for 3 weeks. As previously reported, GN decreased serum calcium levels, but had no effect on lumbar or femoral bone density. In contrast to the in vitro effects, GN had no effect on type I collagen steady-state mRNA levels in the femur; however, it decreased OC steady-state mRNA levels in the femur by 58%. These results suggest that GN has similar in vitro effects in transformed and normal osteoblasts, while the collagen-stimulatory effects observed in vitro cannot be extrapolated to in vivo models. The consistent inhibition of osteocalcin in vitro and in vivo suggests a more specific target for GN that may relate to its effects in inhibiting bone resorption in normal rats.

Identification of a human tumor-derived lipolysis-promoting factor

Our previous studies have demonstrated the production and release of a tumor-derived factor that promoted lipolysis in normal adipocytes. We further demonstrated that this in vitro lipolysis was correlated with the in vivo loss of total carcass lipids induced by the presence of the same tumor. This study identified and isolated this "lipolysis-promoting" factor (LPF), released into the extracellular environment (conditioned media) by the human A375 melanoma cell line, which appears to be responsible for the previously demonstrated induction of in vitro and in vivo lipolytic activity. Unlike previously described non-tumor-derived molecules, such as tumor necrosis factor-alpha/cachectin, which have been implicated in cancer cachexia, the LPF induces alterations in lipid metabolism similar to those observed in cancer patients. The biochemical nature of human tumor-derived LPF appears to be a heat-stable molecule with an apparent molecular weight of approximately 6000. The lipolysis-promoting activity was trichloroacetic acid precipitable, but not precipitable with protamine sulfate or extractable with chloroform:methanol. Its activity appears to be resistant to enzymatic treatments with protease K, trypsin, Pronase, RNase, and DNase, as well as to periodate oxidation. Immunochemically, LPF appears to be distinct from tumor necrosis factor-alpha/cachectin. Furthermore, in contrast to the mechanism of action of tumor necrosis factor-alpha/cachectin, the mechanism of "lipolysis promotion" by LPF appears to be by the induction of cellular lipase activity.