Primary cervical osteomyelitis.

BACKGROUND: Cervical osteomyelitis accounts for only 3-11% of all cases of spinal osteomyelitis, and the diagnosis may be delayed. The characteristics of different pathogens causing cervical osteomyelitis are not fully understood, and there are few established guidelines for treatment. METHODS: The cases of six patients who presented with primary cervical osteomyelitis in the orthopedic department between January 2002 and March 2012 were retrospectively reviewed. All patients had been treated with anterior decompression, instrumentation, and autograft fusion. Data about preoperative and postoperative symptoms, neurological function, pain, C-reactive protein (CRP) levels, and the results of plain film and magnetic resonance imaging were reviewed. RESULTS: Intraoperative cultures revealed Staphylococcus aureus in three patients, Propionibacterium acnes in two, and Mycobacterium tuberculosis in one. The mean duration between symptoms and diagnosis was 7.2 weeks (range, 3-12 weeks). Three patients with S. aureus infections had relatively higher preoperative CRP levels (mean, 173 mg/L) than did the patients with P. acnes infections or tuberculosis (mean, 5.5 mg/L). However, bony destruction was less severe in patients with S. aureus infections than in those patients with P. acnes and tuberculosis. All CRP levels returned to normal in 12 weeks, and all six patients had a final stable cervical alignment and fusion. Ultimately, neurological function and pain score improved in all patients. CONCLUSION: Cervical osteomyelitis caused by S. aureus has an acute onset, higher CRP level, shorter duration from onset to diagnosis and thus causes less bony destruction. By contrast, cervical osteomyelitis caused by P. acnes and tuberculosis has an indolent course, a low or even normal CRP level, a longer duration from onset to diagnosis, and produces more severe bony destruction. Anterior decompression, instrumentation, and autograft fusion can be successfully used to treat primary cervical osteomyelitis. However, a mesh cage can also be a good alternative to an autograft.

Fixation strength of PMMA-augmented pedicle screws after depth adjustment in a synthetic bone model of osteoporosis.

The purpose of this study was to determine the change of fixation strength after adjusting the height of polymethylmethacrylate (PMMA)-augmented pedicle screws.Cement-augmented cannulated pedicle screws with or without PMMA augmentation with a radial hole in the distal third of the screw thread were inserted into synthetic bone blocks used to model osteoporosis. Screws were left unchanged (in situ), screwed in 3 threads, or screwed out 3 threads. The change in screw height was made 24 hours after cement placement. Radiographs of the samples were taken before and after screw adjustment, and pullout strength testing was performed. In the cement group, a radiolucent cavity was present after screwing in due to the screw-cement complex migrating downward, whereas no obvious change in the boneicement complex existed after screwing out. Mean pullout strength was significantly higher in the groups with cement as compared to those without cement. However, in the cement groups, the screw-in group had the lowest mean pullout strength among 3 groups, and the mean pullout strength in the screw-out group was also significantly lower than that in the in situ group (P<.05).Adjustment of pedicle screw height after cement augmentation in a severely osteoporotic spine can significantly reduce the pullout strength of the screw.

Polymethylmethacrylate augmentation of the pedicle screw: the cement distribution in the vertebral body.

Many studies have proven that the polymethylmethacrylate (PMMA) augmentation of the pedicle screw can significantly increase stiffness and strength of spinal fixation. Some major complications have also been reported. However, there are no reports discussing cement distribution and its morphology in the osteoporotic vertebral body, which is critical in the analysis of the biomechanical strength of the pedicle screw and the risk of cement leakage after pedicle screw augmentation. In this study, we used computed tomography (CT) to evaluate the cement distribution in the osteoporotic vertebral body after PMMA augmentation of a pedicle screw and to analyze the factors leading to cement leakage. Two groups of patients were studied. Group A consisted 25 osteoporotic patients (mean age of 73 years) with spinal instrumentation who had a total of 145 pedicle screws and cement augmentation with biopsy needles. Group B consisted of 23 osteoporotic patients (mean age of 74.6 years) with spinal instrumentation who had a total of 125 cannulated pedicle screws with cement augmentation. All patients had CT evaluation of the cement distribution in the vertebral body after the surgery. The cement distribution in the vertebrae was divided into four zones in the axial CT view: anterior one-third, middle third, and posterior third of vertebral body, and the pedicle. The morphology of the cement distribution around the pedicle screw was defined as scattered type or concentrate type. The leakage pattern was divided to anterior-lateral, posterior-lateral, and canal leakage. The correlations among bone mineral density (BMD), the cement leakage rate, and cement distribution morphology were also analyzed. The results showed that most augmented pedicle screws had cement extension into three of the four zones of the vertebral body (66.3%), followed by two zones (20%), all four zones (11.5%), and only one zone (2.2%). Overall, 123 screws (84.8%) in Group A and 108 screws (86.4%) in Group B had cement concentrate type distribution. The cement leakage rate in Group A is 18.3% and 13.6% in Group B. Patients with a BMD <0.6 g/cm(2) had significantly higher rates of cement leakage and tended toward a scattered cement distribution. There was only one patient who had a symptomatic leakage (sciatica) in Group B. We concluded that the cement distribution after pedicle screw augmentation with biopsy needle or cannulated screw technique was mostly localized in three zones of the vertebral body, and patients with lower BMD had a higher risk of cement leakage and scattered cement distribution.

Lateral mass anchoring screws for cervical laminoplasty: preliminary report of a novel technique.

STUDY DESIGN: Preliminary reporting of a group of patients with multiple level cervical spinal stenosis treated with a simple technique using lateral mass anchoring screw and unabsorbable suture line for securing the lamina position after expansive open-door laminoplasty. OBJECTIVE: To develop an improved method for laminoplasty fixation. SUMMARY OF BACKGROUND DATA: Laminoplasty is considered the standard procedure for treating multiple-level cervical spinal stenosis with myelopathy. Keys to successful laminoplasty are expanding and maintaining the spinal canal. There are many techniques for maintaining and securing of the expanded spinal canal such as fascial or joint capsule anchoring suture, spacer interposition, allograft, autograft, or miniplate fixation. However, many reports have indicated that these complicated and/or costly techniques are not superior to other techniques. This study reports a simple, reliable technique using a lateral mass anchoring screw for augmentation of laminoplasty fixation. METHODS: Five patients with multiple level cervical spinal stenosis underwent laminoplasty. A unilateral open door technique was done for the lesion level and the elevated lamina was fixed to lateral mass anchoring screws at each level using unabsorbable suture line. RESULTS: The mean follow-up period was 14.5 months (9 to 34 mo). Postoperatively, the Japanese Orthopedic Association score improved from an average of 8.6 (range: 7 to10 points) to 14.2 points (range: 13 to 15 points). The average recovery rate was 67% (60% to 75%). Follow-up computed tomography scans showed the average improvement in anterioposterior diameter at each level of the cervical canal to be about 4.0 to 7.7 mm. The average open angle at each level was 19.0 to 23.8 degrees. All hinged sides had bony fusion. CONCLUSIONS: Although this is a small series, the preliminary results suggest that this simple lateral mass anchoring screw technique can provide a firm and secure anchor for elevated open lamina in laminoplasty.

Postoperative spinal deep wound infection: a six-year review of 3230 selective procedures.

BACKGROUND: Postoperative wound infection remains a troublesome but common complication after spinal surgery. This study presents the 6-year experience of our surgical team with post-operative deep wound infection in Taipei Veterans General Hospital. METHODS: Of 3230 selected operations, 72 cases of wound infection were identified. Thirty patients with deep wound infection were reviewed, including 17 men and 13 women at a mean age of 32 years. The pre-operative diagnoses included spondylolisthesis, scoliosis, spinal stenosis, herniated inter-vertebral disc, spinal fracture and adjacent syndrome. RESULTS: In this report, different deep wound infection rates were compared between different operative procedures including (1) posterior decompression with fixation and fusion, 1.15%. (2) simple decompression (laminectomy) and disectomy, 0.37%, (3) revision fixation with decompression, 4.4%, and (4) removal of implant. 0.33%. The onset of infection sign was divided into 3 groups: (1) acute (< 2 weeks), 43.3%, (2) subacute (2-4 weeks), 40%, and (3) chronic (> 4 weeks), 16.6%. In 11 patients with deep wound infection, no bacteria was cultured, while 14 patients had Methicillin-resistant Staphylococcus aureus and another 3 patients had lower-grade toxic Staphylococcus aureus. All patients received debridement followed by delayed wound closure with effective antibiotics. Instruments were removed in only 8 patients. Twenty seven cases were cured after treatment but 3 patients expired in poor condition. CONCLUSIONS: In this series, total deep wound infection was 0.9% in our 6-year experience. The incidence of postoperative spinal infection increased with the complexity of the procedure. Most patients got completely disease free with antibiotics and surgical treatment.

Flexion-distraction injury of the thoracolumbar spine.

Flexion-distraction injury of the thoracolumbar spine results from a failure of both the posterior and middle columns under tension, and this injury is uncommon. Progressive kyphotic deformity frequently develops after conservative treatments. We report our 10 years' experience with the surgical treatment of flexion-distraction injuries. From January 1991 to December 2000, 30 flexion-distraction thoracolumbar spinal injuries were treated at our hospital. We included 23 patients in this study, and seven patients were excluded. The mean age of the patients was 37.2 years. Six were female and 17 were male. All patients received open reduction, posterior instrumentation, and posterior fusion at the level of injury. Post-operatively, patients were all placed in total contact orthoses for 3 months. Ambulation was allowed immediately after brace application.The mean follow-up period was 84.7 months follow-up. The final average follow-up kyphotic angulation was 5.4 degrees, which is an average improvement of 9.5 degrees. Post-operative back pain ratings indicated that result of surgery was mostly good, and the neurological evaluation was almost normal after long-term follow-up. A satisfactory reduction and good stabilisation with solid fusion was achieved in all cases, without any significant loss of reduction. Surgical treatment of reduction and stabilisation with posterior instrumentation and fusion is suggested in patients with flexion-distraction injury of the thoracolumbar spine.

One-stage posterior surgery for treatment of advanced spinal tuberculosis.

BACKGROUND: It is not uncommon that some patients in poor general condition and advanced spinal tuberculosis cannot proceed with the staged anterior spinal surgery after posterior instrumentation. We demonstrated a group of patients with advanced spinal tuberculosis that were treated posterior procedure alone. METHODS: From January 1993 to January 2001, 12 patients in our hospital in poor general condition and advanced spinal tuberculosis-marked abscess with angular deformity more than 25 degrees and/or spinal canal compromised more than 30%, were treated in our hospital with posterior instrumentation and chemotherapy only. All patients were immobilized postoperatively with orthosis until solid fusion was noted on bony graft. The chemotherapy persisted for at least 12 months in all patients. RESULTS: Spontaneous bony fusion of vertebrae at 1-year follow-up averaged 75%. Solid union on posterior or posterolateral fusion was about 91.7%. Implant loosening and deep wound infection were noted in 2 of the patients respectively. We assessed the functional results with the postoperative activity condition, symptom relief and medication dependence in the 6th month after the spinal surgery. Seven cases of the 12 patients (58.3%) had good to excellent results in this series. CONCLUSIONS: The one-stage posterior surgery adjunct with chemotherapy is a considerable and alternative treatment for patients with advanced spinal tuberculosis and in poor general condition.