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.

Hematogenous pyogenic facet joint infection.

STUDY DESIGN: Retrospective. OBJECTIVES: To determine the incidence, clinical presentation, diagnostic laboratory values, imaging characteristics, and optimal treatment of hematogenous pyogenic facet joint infections. SUMMARY OF BACKGROUND DATA: There are 27 documented cases of hematogenous pyogenic facet joint infections. Data regarding incidence, clinical presentation, diagnosis, and treatment response are incomplete because of the paucity of reported cases. METHODS: This is a retrospective study of all cases of hematogenous pyogenic facet joint infection treated at one institution. Data from previous publications were combined with the present series to identify pertinent clinical characteristics and response to treatment. RESULTS: A total of six cases (4%) of hematogenous pyogenic facet joint infection were identified of 140 cases of hematogenous pyogenic spinal infection at our institution. Combining all reported cases reveals the following: The average patient age is 55 years. Ninety-seven percent of cases occur in the lumbar spine. Epidural abscess formation complicates 25% of the cases of which 38% develop severe neurologic deficit. Erythrocyte sedimentation rate and C-reactive protein are elevated in all cases. Staphylococcus aureus is the most common infecting organism. Magnetic resonance imaging is accurate in identifying the septic joint and associated abscess formation. Percutaneous drainage of the involved joint has a higher rate of success (85%) than treatment with antibiotics alone (71%), but the difference is not significant (P = 0.37). CONCLUSIONS: Hematogenous pyogenic facet joint infection is a rare but underdiagnosed clinical entity. Facet joint infections may be complicated by abscess formation in the epidural space or in the paraspinal muscles. Uncomplicated cases treated with percutaneous drainage and antibiotics may fare better than those treated with antibiotics alone. Cases complicated by an epidural abscess and severe neurologic deficit should undergo immediate decompressive laminectomy.

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.

Percutaneous transpedicular discectomy and drainage in pyogenic spondylodiscitis.

The natural history of uncomplicated hematogenous pyogenic spondylodiscitis is self-limiting healing. However, a variable degree of bone destruction frequently occurs, predisposing the spine to painful kyphosis. Delayed treatment may result in serious neurologic complications. Early debridement of these infections by percutaneous transpedicular discectomy can accelerate the natural process of healing and prevent progression to bone destruction and epidural abscess. The purpose of this manuscript is to present our technique of percutaneous transpedicular discectomy (PTD), to revisit this minimally invasive surgical technique with stricter patient selection, and to exclude cases of extensive vertebral body destruction with kyphosis and neurocompression by epidural abscess, infected disc herniation, and foraminal stenosis. In a previously published report of 28 unselected patients with primary hematogenous pyogenic spondylodiscitis, the immediate relief of pain after PTD was 75%, and in the long-term follow-up, the success rate was 68%. Applying stricter patient selection criteria in a second series of six patients (five with primary hematogenous spondylodiscitis and one with secondary postlaminectomy-discectomy spondylodiscitis), all patients with primary hematogenous spondylodiskitis (5/5) experienced immediate relief of pain that remained sustained at 12-18 months follow-up. This procedure was not very effective, however, in the patient who suffered from postlaminectomy infection. This lack of response was attributed to postlaminectomy-discitis instability. The immediate success rate after surgery for unselected patients in this combined series of 34 patients was 76%. This technique can be impressively effective and the results sustained when applied in the early stages of uncomplicated spondylodiscitis and contraindicated in the presence of instability, kyphosis from bone destruction, and neurological deficit. The special point of this procedure is a minimally invasive technique with high diagnostic and therapeutic effectiveness.