Hematogenous pyogenic spinal infections and their surgical management.

STUDY DESIGN: Mainly a retrospective study of 101 cases of pyogenic spinal infection, excluding postoperative infections. Data were obtained through medical record review, imaging examination, and patient follow-up evaluation. SUMMARY OF BACKGROUND DATA: Hematogenous pyogenic spinal infection has been described variously as spondylodiscitis, discitis, vertebral osteomyelitis, and epidural abscess. Recommended treatment options have included conservative methods (antibiotics and bracing) and surgical intervention. However, a comprehensive classification that would aid in diagnosis, treatment planning, and prognosis has not yet been devised. OBJECTIVES: To analyze the bacteriology, pathologic entities, complications, and results of treatment options for pyogenic spinal infection. METHOD: All patients received plain radiographs, gadolinium-enhanced magnetic resonance imaging scans, and bone/gallium radionuclide studies. All patients had tissue biopsies. Bacteriology, hematology, and predisposing factors were analyzed. All patients received intravenous and oral antibiotics. A total of 58 patients underwent surgery. Patient outcomes were correlated with clinical status, with treatment method and, where applicable, with location and nature of epidural compression. Statistical analyses were performed. RESULTS: Spondylodiscitis occurred most commonly with primary epidural abscess, spondylitis, discitis, and pyogenic facet arthropathy, all occurring rarely. Staphylococcus aureus was the main organism. Infection elsewhere was the most common predisposing factor. Leukocyte counts were elevated in 42.6% of spondylodiscitis cases. The erythrocyte sedimentation rate was elevated in all cases of epidural abscess. There were 35 cases of epidural abscess (frank abscess, 29; granulation tissue, 6). Epidural abscess complicating spondylodiscitis occurred most often in the cervical spine, followed by thoracic and lumbar areas. The rate of paraplegia or paraparesis also was highest in cervical and thoracic regions. There were no cases of quadriplegia. All patients with either epidural granulation tissue or paraparesis recovered completely after surgical decompression. Only 18% of patients with frank epidural abscess and 23% of patients with paralysis recovered completely after surgical decompression. Patients with spondylodiscitis who were treated nonsurgically reported residual back pain more often (64%) than patients treated surgically (26.3%). CONCLUSIONS: Pyogenic spinal infection can be thought of as a spectrum of disease comprising spondylitis, discitis, spondylodiscitis, pyogenic facet arthropathy, and epidural abscess. Spondylodiscitis is more prone to develop epidural abscesses in the cervical spine (90%) than the thoracic (33.3%) or lumbar (23.6%) areas. Thecal sac neurocompression has a greater chance of causing neurologic deficit in the thoracic spine (81.8%). Treatment of neurologic deficit caused by epidural abscess is prompt surgical decompression, with or without fusion. Patients with frank abscess had less favorable outcomes than those with granulation tissue, and paraplegia responded to treatment more poorly than paraparesis. Surgery was preferable to nonsurgical treatment for improving back pain.

Work-related low back injuries caused by unusual circumstances.

Expanding the knowledge of issues that surround work-related injuries allows for the development of more successful work accident prevention policies, treatment and rehabilitation protocols, and education programs. Specifically, clinical observation indicated that many patients did not perceive or report the circumstances of the injury as being part of their regular duties. The objective of this study was to investigate whether unusual activities or circumstances at work played any significant role in the rehabilitation of patients with disabling low back pain. Four hundred thirty-seven patients with severe disabling pain due to work-related injuries and surgery as an option for treatment were studied. The circumstances at the time of the accident were investigated, including demographic data, type of job held at the time of injury, rapport with supervisor, recent cutbacks in job force, and number of highly related injuries. Thirty-three percent of workers were injured while performing their ordinary job duties, with lifting implicated as the most common cause of injury (66%) followed by pushing/pulling (13%). In most patients (67%), the injury occurred under unusual circumstances or activities not normally described in the worker's job routine. This finding has not been previously addressed and implies that physical therapists can improve patient confidence about rehabilitation and returning to work by educating the patients about these circumstances.

Pathomechanics and clinical relevance of disc degeneration and annular tear: a point-of-view review.

Annular tear is a major cause of intervertebral disc degeneration that results in disabling back pain. Many of the stresses resulting in this type of lesion are common in the workplace: compression, torsion, compression combined with flexion, and vibration. Age-related disc degeneration begins early in adulthood, and progresses thereafter, altering disc morphology and mechanical properties in ways that predispose to disc herniation, and should not be misconstrued as "old age." Acute trauma may produce disc herniation whether or not there are predisposing factors, such as age-related degeneration, but disc herniation in the absence of acute injury requires the presence of preexisting degenerative changes.

The effectiveness of gallium citrate Ga 67 radionuclide imaging in vertebral osteomyelitis revisited.

We investigated the role of gallium citrate Ga 67 scanning in diagnosing spondylodiscitis. Scans of 41 patients with suspected spondylodiscitis showed increased radionuclide uptake in 39 patients; these findings correlated with those of magnetic resonance imaging and were proved by biopsy. Two patients with negative findings on gallium scans had been strongly suspected of having spondylodiscitis; biopsy findings in these patients showed degenerative changes. Thirteen patients had negative cultures, while 22 had polygenic infections and 4 had granulomatous infections. Gallium scanning proved to be 100% sensitive, specific, and accurate. The interrater accuracy was excellent. Follow-up scans were used to track therapeutic progress. We recommend complementary bone and gallium scans in cases of suspected spinal infections. If the scan is positive, a biopsy should be done. If the scans are negative, no further investigation is needed.

Techniques and pitfalls of cervical lateral mass plate fixation.

We studied 35 successive patients who underwent subaxial lateral mass fixation between June 1994 and January 1996. Follow-up ranged from 2 to 3 1/2 years. Postoperative computed tomography scans showed 45 of 146 screws (31%) had suboptimal trajectory, but only 2 screws minimally impinged the foramen transversarium without adverse sequelae. The fusion rate was 89%. Study results show that optimal drilling technique and trajectory (15 degrees-25 degrees rostral in the sagittal plane, 20 degrees-30 degrees lateral in the axial plane) and intraoperative somatosensory evoked potential monitoring are associated with good screw placement and avoidance of complications, and bone grafting is associated with higher fusion rates.

Blastomycosis of the lumbar spine: case report and review of the literature, with emphasis on diagnostic laboratory tools and management.

We report on the conservative and surgical management of a patient with blastomycosis of the lumbar spine, causing severe and crippling deformity. The diagnosis was made through biopsy. Curative removal, reconstruction and realignment of the spine were achieved. Imaging modalities were highlighted, with a detailed discussion of the histology and conservative and surgical management. We emphasize the importance of early, aggressive treatment of blastomycosis to prevent deformity and disability, and to enable identification of the best management of a destructive lesion with deformity. This case demonstrates that empirical treatment should not be used in cases of unusual sinus and abscess locations. Specific diagnosis and early treatment are indicated to prevent dreadful complications and spinal deformity resulting from blastomycosis. Aggressive antifungal therapy can cure the disease but does not control complications related to deformity. The latter can only be addressed by surgical reconstruction. We review the literature of surgical treatment, focusing on abscess drainage, bone fusion and posterior instrumentation in the absence of addressing the deformity component.

Torsional injury resulting in disc degeneration in the rabbit: II. Associative changes in dorsal root ganglion and spinal cord neurotransmitter production.

The mechanism mediating the chronic pain associated with lumbar disc degeneration may involve neurotransmitters elaborated by dorsal root ganglion (DRG). This hypothesis has been tested in an applicable rabbit model of disc degeneration. Twenty control male rabbits underwent a soft-tissue release; 20 experimental rabbits sustained a facetectomy and capsulotomy and received an acute torsional lumbar injury. The levels of calcitonin gene-related peptide, vasoactive intestinal peptide, and substance P were measured in the DRG, spinal cord, and disc at 10, 30, 60, and 90 days postoperatively. Torsional injury was associated with a statistically significant increase in most DRG and spinal cord neurotransmitter values after 60-90 days. These points in time marked the periods of maximum biomechanical instability and disc narrowing. Such data support concepts about the association between chronic lumbar spinal instability, disc degeneration, and pain.

Torsional injury resulting in disc degeneration: I. An in vivo rabbit model.

Torsional injuries may be a precursor to intervertebral disc degeneration, but published rabbit models indicate a latent time of 6 months. We describe a rabbit model in which instability and disc degeneration appear within 3 months. Sixty-five male New Zealand rabbits underwent presurgical irradiation to inhibit heterotopic bone formation. Control animals then underwent either a soft-tissue release or facetectomy and capsulotomy, whereas experimental animals received surgery and an acute 30 degrees torsional lumbar injury. Capsulotomy, as well as facetectomy without torsion, failed to effect disc degeneration. However, the rabbits that received torsion exhibited clear indications of degenerative disc changes (thinning, increased PLA2 levels, and decreased nucleus pulposus volume) within 60-90 days. The observations associate disc degeneration with a destabilizing acute torsional injury.