Correction to: Staged surgery for tandem cervical and lumbar spinal stenosis: Which should be treated first?

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Instrumented Posterolateral fusion versus instrumented Interbody fusion for degenerative lumbar diseases in uremic patients under hemodialysis.

BACKGROUND: Advances in hemodialysis have facilitated longer lifespan and better quality of life for patients with end stage renal disease (ESRD). Symptomatic degenerative lumbar diseases (DLD) becomes more common in patients with ESRD. Posterior instrumented fusion remains popular for spinal stenosis combining instability. Only a few sporadic studies mentioned about surgical outcomes in patients with ESRD underwent spine surgeries, but no one discussed about which fusion method was optimal for this kind of patients. In this study, we compared the differences between lumbar posterolateral fusion (PLF) and lumbar interbody fusion (IBF) in uremic patients underwent instrumented lumbar surgeries. METHODS: Between January 2005 and December 2017, ESRD patients under maintenance hemodialysis underwent posterior instrumented fusion for DLD were reviewed. A PLF group and an IBF group were identified. The demographic data was collected using their medical records. Clinical outcomes were evaluated by Oswestry Disability Index (ODI) and the visual analogue scale (VAS); radiographic results were assessed using final fusion rates. Any surgical or implant-related complication was documented. RESULTS: A total of 34 patients (22 women and 12 men, mean age of 65.4 years) in PLF group and 45 patients (26 women and 19 men, mean age of 65.1 years) in IBF group were enrolled. Both groups had similar surgical levels. The operation time was longer (200.9 vs 178.3 min, p = 0.029) and the amount of blood loss was higher (780.0 vs 428.4 ml, p = 0.001) in the IBF group. The radiographic fusion rate was better in the PLF group but without significant difference (65.2% vs 58.8%, p = 0.356). Seven in the PLF group and ten in the IBF group developed surgical complications (20.5% vs. 22.2%, p = 0.788); three patients in the PLF group (8.8%) and five patients in the IBF group (11.1%) received revision surgeries because of implant-related or wound complications. Comparing to preoperative ODI and VAS, postoperative ODI and VAS obtained significant improvement in both groups. CONCLUSIONS: Successful fusion rates and clinical improvement (VAS, ODI) were similar in IBF and PLF group. Uremic patients underwent IBF for DLD had longer length of operation and higher operative blood loss than underwent PLF.

Staged surgery for tandem cervical and lumbar spinal stenosis: Which should be treated first?

PURPOSE: Tandem spinal stenosis (TSS) refers to lumbar and cervical spinal canal stenosis. Staged surgery is often chosen, but sometimes, mere decompression of one stenosis is adequate to relieve symptoms. Therefore, we intend to analyze whether starting with the cervical or the lumbar region is the most logical option. METHODS: We retrospectively reviewed the data of 47 patients with TSS, having first-stage decompression for the most symptomatic stenosis, and classified into two groups (Group A: lumbar decompression first, Group B: cervical decompression first). Postoperative outcomes were analyzed for at least 2 years, and they were cautiously watched for symptoms of the non-operated stenosis; if such symptoms were debilitating, second-stage surgery for the non-operated stenosis was done. RESULTS: The demographic characteristics of Group A (n = 11) and Group B (n = 36) were comparable. One patient (9%) in Group A and 25 patients (67%) in Group B had resolution of symptoms and good functional recovery. The need for a second-stage surgery for the non-operated stenosis was significantly high (p = 0.001) among patients in Group A. They suffered a significant worsening of both the mJOA score and the Nurick's grade; whereas, patients in Group B experienced staged improvement of both scales. CONCLUSION: First-stage surgery for the cervical stenosis significantly lowers the need of the second-stage surgery. In contrast, if lumbar stenosis was treated first, a dramatic exacerbation of the symptoms related to the cervical stenosis can occur soon. Therefore, treatment of cervical stenosis first seems to be more appropriate. These slides can be retrieved under Electronic Supplementary Material.

The correlations between the anchor density and the curve correction of adolescent idiopathic scoliosis surgery.

BACKGROUND: The optimal anchor density in adolescent idiopathic scoliosis (AIS) surgery to achieve good curve correction remains unclear. The purpose of the study is to analyze the correlations between three-dimensional curve correction and anchor density in the pedicle screw-based posterior fusion of AIS. METHODS: One hundred and twenty-seven AIS patients receiving primary posterior fusion with pedicle screw instrumentation were retrospectively reviewed. Anchor density (AD) was defined as the screws number per fused spinal segment. The correlations between three-dimensional curve correction radiographic parameters and anchor density were analyzed with subgroup analysis based on different curve types, curve magnitudes, and curve flexibilities. The differences of curve correction parameters between the low-density (AD ≤1.4), middle-density (1.4 < AD ≤1.7) and high-density (AD > 1.7) groups were also calculated. Independent t-test, analysis of variance (ANOVA), and Pearson's correlation coefficient were used for statistical analysis. RESULTS: There were no correlations between the anchor density and the coronal curve correction or apical vertebral rotation (AVR) correction. In the sagittal plane, mild positive correlations existed between anchor density and thoracic kyphosis correction in all patients (r = 0.27, p = 0.002). Subgroup analysis revealed similar mild positive correlations in Lenke 1 (r = 0.31, p = 0.02), Lenke 1-3 (r = 0.27, p = 0.01), small curves (40°-60°, r = 0.38, p <  0.001), and flexible curves (flexibility > 40%, r = 0.34, p = 0.01). There were no differences between low-density (mean 1.31), middle-density (mean 1.55), and high-density (mean 1.83) in terms of coronal or axial curve correction parameters. Low-density group has longer fused level (mean difference 2.14, p = 0.001) and smaller thoracic kyphosis correction (mean difference 9.25°, p = 0.004) than high-density group. CONCLUSION: In our study, the anchor density was not related to coronal or axial curve corrections. Mild positive correlations with anchor density were found in thoracic kyphosis correction, especially in patients with smaller and flexible curves. Low anchor density with longer fusion level achieves similar curve corrections with middle or high anchor density in adolescent idiopathic scoliosis surgery.

Cage positioning as a risk factor for posterior cage migration following transforaminal lumbar interbody fusion - an analysis of 953 cases.

BACKGROUND: The risk of posterior cage migration (PCM) exists when a fusion cage is used for transforaminal lumbar interbody fusion (TLIF). This complication is influenced by contact pressure between the endplate and the cage. Previous reports demonstrated that anteriorly located cages bore more load and had greater strain than posteriorly located cages. However, there have been no detailed reports on the correlation between cage positioning and PCM. METHODS: From March 2014 to October 2015, we reviewed 953 patients receiving open transforaminal lumbar interbody fusion (TLIF) and bilateral pedicle screw instrumentation. One hundred patients without PCM were randomly sampled as the control group. Postoperative sagittal and coronal cage positions in the disc space were evaluated with the 'depth ratio' and the 'coronal ratio'. The demographic data of patients with and without PCM were compared to detect patient-related factors. Radiographic and cage related parameters, including cage position, preoperative disc height, preoperative spine stability, cage geometry, cage size, and height variance (= cage height - preoperative disc height) were compared between the PCM group and the control group. Univariate analyses and a multivariate logistic model were used to identify risk factors of PCM. RESULTS: Posterior cage migration occurred in 24 (2.52%) of 953 patients. The univariate and multivariate analyses revealed that those with a decreased depth ratio (OR, 9.78E-4; 95% CI, 9.69E-4 - 9.87E-4; p < 0.001) and height variance (OR, 0.757, 95% CI, 0.575-0997, p = 0.048) had a significantly higher risk of developing PCM. CONCLUSIONS: Our results verified that posteriorly located cages and undersized cages are more prone to developing PCM, which may aid surgeons in making optimal decisions during TLIF procedures.

Application of two-parameter scoliometer values for predicting scoliotic Cobb angle.

BACKGROUND: Adolescent idiopathic scoliosis, in which obvious curves are visible in radiographic images, is also seen in combination with lumps in the back. These lumps contribute to inclination, which can be measured by a scoliometer. To the authors' knowledge, there are no previous formulas combining thoracic and lumbar scoliometer values simultaneously to predict thoracic and lumbar Cobb angles, respectively. This study aimed to create more accurate two-parameter mathematical formulas for predicting thoracic and lumbar Cobb angles. METHODS: Between Dec. 2012 and Jan. 2013, patients diagnosed with idiopathic scoliosis in an outpatient clinic were enrolled. The maximal trunk rotations at the thoracic and lumbar regions were recorded with a scoliometer. Right asymmetry hump was deemed positive (+), and left asymmetry hump was deemed negative (-). The Cobb angles were measured with a Picture Archiving and Communication System. Statistical analysis included Pearson's correlation coefficient, multivariate regression and Bland-Atman analysis. RESULTS: One-hundred and one patients were enrolled in our study. The average thoracic curve (TC) was 23.3 ± 1.8°, while the average lumbar curve (LC) was - 23.3 ± 1.4°. The thoracic inclination (TI) and lumbar inclination (LI) were 4.5 ± 0.7 and - 5.9 ± 0.6, respectively. The one-parameter formula for the thoracic curve was TC = 2.0 TI + 14.3 (r = 0.813); for the lumbar curve, it was LC = 0.9 LI - 16.9 (r = 0.409). By multivariate regression, the two-parameter formulas for the thoracic and lumbar curves were TC = 2.6 TI - 1.4 LI (r = 0.931) and LC = - 1.5 TI + 2.0 LI (r = 0.874), respectively. The two-parameter formulas were more accurate than the one-parameter formulas. CONCLUSIONS: Based on the results of these two-parameter formulas for thoracic and lumbar curves, the Cobb angles can be predicted more accurately by the readings of the scoliometer. Physicians and other healthcare practitioners can thus evaluate patients with scoliosis more precisely than before with a scoliometer.

Intraoperative electromyographic monitoring to optimize safe lumbar pedicle screw placement - a retrospective analysis.

BACKGROUND: The foremost concern of a surgeon during pedicle screw fixation is safety. Assistive modalities, especially intraoperative electromyographic monitoring (EMG) can function as an essential tool to recognize screw malposition that compromise neural integrity, so that the screws can be repositioned immediately rather than later. We intend to study the efficacy of intraoperative EMG monitoring to detect potential pedicle breach and evaluate whether reoperation rates were significantly reduced. METHODS: Retrospectively, patients who underwent posterior stabilization with pedicle screws for various pathologies were analysed and those with screws among L1-S1 levels were shortlisted. They were divided into two groups. Group 1 included patients in whom trigger EMG (t-EMG) was used to confirm appropriate screw placement and Group 2 included those in whom it was not used. Responses to t-EMG and corresponding stimulation thresholds were recorded for Group 1 patients. The sensitivity and specificity of the test was calculated. Reoperation rates due to postoperative neurologic compromise caused by malpositioned screws were compared between both the groups. RESULTS: A total of 518 patients had 3112 pedicle screws between L1-S1 levels. Among Group 1 [n = 296; Screws = 1856], 145 screws (7.8%) showed a positive response for t-EMG at stimulation thresholds ranging between 2.6 to 19.8 mA. The sensitivity and specificity of t-EMG to diagnose potential pedicle breach was found to be 93.33% and 92.88% respectively. Only one patient among Group 1 required reoperation. However, among Group 2 [n = 222; screws = 1256], six patients required reoperation. This indicated a significant decrease in the number of malpositioned screws that caused neurological compromise [p = 0.02], leading to subsequent decrease in reoperation rates [p = 0.04] among Group 1 patients. CONCLUSIONS: Trigger EMG is well efficient in detecting potential pedicle screw breaches that might endanger neural integrity. In combination with palpatory and radiographic assessment, it will certainly aid safe and secure pedicle screw placement. It can also efficiently reduce reoperation rates due to neurologic compromise provoked by a malpositioned screw.

Early surgery with antibiotics treatment had better clinical outcomes than antibiotics treatment alone in patients with pyogenic spondylodiscitis: a retrospective cohort study.

BACKGROUND: Pyogenic spondylodiscitis is a form of spinal infection that can result in severe back pain and even death. However, information is lacking on the relative effectiveness of various therapies. A retrospective chart review was conducted to investigate whether early surgical treatment of pyogenic spondylodiscitis coupled with intravenous antibiotics results in better patient prognoses than intravenous antibiotics therapy alone. METHODS: All patients treated for pyogenic spondylodiscitis at a single medical center from July 2006 to July 2011 were retrospectively reviewed. The inclusion criteria consisted of diagnosis of an early stage infection without neurological deficit, and patients without severe sepsis who were suitable candidates for early surgery as determined by a Pittsburgh bacteremia score < 4, and patients with delayed diagnosis and lost to outpatient follow-up were excluded. Clinical outcomes included patient demographic data, kyphosis angle, length of treatment, Oswestry Disability Index and visual analogue pain scale were analyzed. RESULTS: Of 90 enrolled patients, Group 1 (n = 47) received only antibiotic therapy and Group 2 (n = 43) received early surgery with post-surgery antibiotics for 2 to 4 weeks. Group 2 exhibited significantly better results than Group 1 for mean antibiotic administration period, mean hospitalization period, kyphotic angle correction. Of 61 patients who participated in telephone follow-up after discharge, Group 2 (n = 26) had significant lower mean ODI score, and mean back pain score than Group 1 (n = 35). CONCLUSIONS: While infection control was similar for both groups, patients treated with early surgery and antibiotics were hospitalized for fewer days and required less antibiotics than those treated with antibiotics alone, also having better functional outcomes. In short, early surgical treatment of pyogenic spondylodiscitis typically achieves a better prognosis, shorter hospitalization period, and subsequent significant improvement in kyphotic deformity and quality of life.

Is additional balloon Kyphoplasty safe and effective for acute thoracolumbar burst fracture?

BACKGROUND: Burst fracture is a common thoracolumbar injury that is treated using posterior pedicle instrumentation and fusion combined with transpedicular intracorporeal grafting after reduction. In this study, we compared the outcome of these two techniques by using radiologic imaging and functional outcome. METHODS: Sixty-one patients with acute thoracolumbar burst fracture were operated with kyphoplasty (n = 31) or vertebroplasty (n = 30) and retrospectively reviewed in our institution between 2011 and 2014. All 61 patients underwent surgery within 5 days after admission to the hospital and then followed-up for 12 to 24 months after surgery. RESULTS: Significant improvement was found in the anterior vertebral height (92 ± 8.9% in the kyphoplasty group, 85.6 ± 7.2% in the vertebroplasty group, p < 0.01) at 1 month post-operatively and (89 ± 7.9% in the kyphoplasty group, 78 ± 6.9% in the vertebroplasty group, p < 0.01) at the 24-month follow-up. Significant improvement was also observed in the kyphotic angle (1.2 ± 0.5° in the kyphoplasty group, 10.5 ± 1.2° in the vertebroplasty group, p < 0.01) at 1 month post-operatively and (5.4 ± 1.2° in the kyphoplasty group, 11.5 ± 8.5° in the vertebroplasty group, p < 0.01) at the 24-month follow-up. Both operations led to significant improvement of the patients' pain and the Oswestry disability index (p < 0.01). Cement leakage was noted in 29% of patients after kyphoplasty and 77% of patients after vertebroplasty (p < 0.01). Only one implant failure (3.3%), which required further surgical intervention, was reported in the vertebroplasty group. CONCLUSIONS: Reduction with additional balloon at the fractured site is better than indirect reduction only by posterior instrumentation. The better reduction of kyphotic angle and the lower cement leakage rate in the kyphoplasty group indicate that additional balloon kyphoplasty is safe and effective for acute thoracolumbar burst fracture.

Correlation of blood bone turnover biomarkers and Wnt signaling antagonists with AS, DISH, OPLL, and OYL.

BACKGROUND: Wnt signaling plays an important role in development and maintenance of many organs and tissues. The most-studied secreted Wnt inhibitors are sclerostin (SOST), Dickkopf-related protein 1 (DKK-1), and secreted frizzled related protein 1 (SFRP-1) which play important roles in bone turnover. The present study investigated the relationship between serum Wnt inhibitors and diseases with excessive ossification structures, such as ossification of posterior longitudinal ligament (OPLL), ankylosing spondylitis (AS), diffuse idiopathic skeletal hyperostosis (DISH), and ossification of yellow ligament (OYL). METHODS: Twenty-five patients with AS, DISH, OPLL, or OYL were recruited in this study. Fasting peripheral blood samples were collected from all patients and nine controls. Various biomarkers of bone turnover including osteocalcin (OSC), osteoprotegerin (OPG), SFRP-1, DKK-1, and SOST were investigated. RESULTS: Our data showed that serum levels of OSC were higher, but Dkk-1 levels were lower in AS, DISH, OPLL, and OYL patients than those in the controls. Serum levels of SFRP-1 were significantly higher in DISH patients than those in the controls. Serum levels of SOST were significantly higher in DISH and OPLL patients than both levels in the controls. Serum levels of OPG were lower in AS patients than those in the controls. Serum levels of OSC were higher in the OPLL patients than those in the AS patients. Serum levels of DKK-1, SFRP-1, SOST, and OPG were not significantly different between the different disease groups. CONCLUSIONS: In this exploratory study, both OSC and DKK-1 levels are correlated with the clinical conditions associated with excessive ossification, indicating that blood OSC and DKK-1 levels may serve as diagnostic biomarkers for AS, DISH, OPLL, and OYL. These findings may also help discover potential drug therapies for management of these diseases in the future.

Comparison between harvesting and preserving the spinous process for adolescent idiopathic scoliosis.

BACKGROUND: Spinous process has been routinely resected during posterior fusion of adolescent idiopathic scoliosis for fusion bed preparation and local autologous bone graft supplement. However, spinous process serves as an important structure in posterior ligament complex and was the anchorage of paraspinal muscle groups. With the development of pedicle screws instrumentation and the potential fusion ability in children, the need for resecting spinous process in this procedure could be further investigated. The purpose of this study was to compare the fusion rates, surgical outcomes and complications between harvesting and preserving the spinous process in posterior fusion of adolescent idiopathic scoliosis. METHODS: From January 2003 to December 2008, 104 consecutive adolescent idiopathic scoliosis patients underwent primary posterior fusion with local autologous bone grafts and following for a minimum of 24 months were reviewed. The patients were divided into a harvesting group (n = 61) with the spinous process harvested, and a preserving group (n = 43) with the spinous process preserved. Blood loss, radiographic assessments, and clinical outcomes were compared between the two groups. RESULTS: There were no significant differences in duration of surgery and peri-operative blood transfusion between the two groups. However, blood loss was statistically greater (983 ± 446 ml vs. 824 ± 361 ml; p = 0.048) and duration of hospitalization was statistically longer (7.4 ± 1.0 days vs. 6.8 ± 0.8 days; p = 0.003) in the harvesting group. The pre- and post-operative structural curves, correction rates, sagittal profile and loss of corrections were similar in both groups. Based on radiographic evaluation, the incidences of pseudoarthrosis were similar in both groups (3/61 vs. 2/43; p = 0.95). The incidence of prescribing pain medication for back discomfort during follow-up was statistically higher in the harvesting group (16/61 vs. 4/43; p = 0.03). CONCLUSIONS: The surgical outcomes and fusion rates between harvesting and preserving the spinous process were comparable. Resecting the spinous process as local autologous bone graft may not be necessary in posterior fusion for adolescent idiopathic scoliosis patients.

Surgical outcomes after instrumented lumbar surgery in patients of eighty years of age and older.

BACKGROUND: In Taiwan, the life expectancy of an 80-year-old man is 88.4 years and the life expectancy of an 80-year-old woman is 89.8 years. Some of these people will develop symptomatic degenerative lumbar diseases that interfere with an active lifestyle. These older surgical candidates usually ask the surgeon whether it would be safe to undergo surgery. However, there is no literature assessing the outcomes of laminectomy, fusion and posterior fixation for degenerative lumbar diseases in patients older than 80 years. The purpose of this study was to report the surgical outcomes of patients 80 years of age and older who underwent spinal decompression and instrumented lumbar arthrodesis for degeneration lumbar diseases. METHODS: We retrospectively reviewed patients with degenerative lumbar diseases and spinal stenosis who underwent surgery between January 2010 and December 2012. Inclusion criteria were age greater than or equal to 80 years, decompression with instrumented lumbar arthrodesis, and at least 2 years of follow-up. Totally 89 patients were studies. Clinical outcomes were evaluated according to the Oswestry Disability Index (ODI) and visual analogue scale (VAS) of leg and back pain. Plain radiographs (lateral, anteroposterior, and flexion-extension) were used to assess the status of fusion and implant-related complications. Every complication during admission and any implant-related or failed-back syndrome requiring a second surgery was documented. T test and Fisher's exact test were used for statistical analysis. RESULTS: Five patients were lost to follow-up, and another 12 died during the follow-up period. One patient died due to cerebral stroke just 2 days after surgery, and the other 11 patients passed away 3 months to 4 years postoperatively. In all, 72 patients had an adequate follow-up: 44 were female and 28 were male. The average age at surgery was 82.5 ± 2.6 years (80 to 93); 63 patients underwent their first lumbar surgery, and nine patients received a second surgery. Patients underwent arthrodesis surgeries were from a single-level to a 7-level. Four patients developed complications (5.6 %, 4/72). At the final follow-up, the average ODI score was lower than the preoperative score (30.0 vs. 61.8) (p < 0.001). The average VAS score also showed improvement (leg: p < 0.001; back: p < 0.001). Forty-three patients were classified as "satisfied", and 29 were "dissatisfied". Longer operation time (p = 0.014) and development of complications (p = 0.049) were related to poor clinical results. Radiographic follow-up showed that 53 patients had solid union, ten had a probable union, and nine had pseudarthrosis. More surgical segments led to a greater chance of pseudarthrosis (2.0 ± 0.9 vs 3.0 ± 1.8, p = 0.003). CONCLUSION: Longer instrumented segments and development of complications contributed to worse clinical and radiographic outcomes. With proper patient selection, posterior decompression with instrumented fusion can be safe and effective for patients 80 years of age and older with degenerative lumbar conditions.

Unplanned revision spinal surgery within a week: a retrospective analysis of surgical causes.

BACKGROUND: The need for revision surgery after a spinal surgery can cause a variety of problems, including reduced quality of life for the patient, additional medical expenses, and patient-physician conflicts. The purpose of this study was to evaluate the causes of unplanned revision spinal surgery within a week after the initial surgery in order to identify the surgical issues most commonly associated with unplanned revision surgery. METHODS: We retrospectively reviewed the medical records of all patients at who received a spinal surgery at a regional medical center from July 2004 to April 2011 in order to identify those who required a revision surgery within one week of their initial surgery. Patients were excluded if they received a vertebroplasty, kyphoplasty, or nerve block surgery, because those surgeries are one-day surgeries that do not require hospital admission. In addition, patients with a primary diagnosis of wound infection were also excluded since reoperations for infection control can be expected. RESULTS: The overall incidence of unplanned revision spinal surgery during the time period covered by this review was 1.12% (116/10,350 patients). The most common surgical causes of reoperation were screw malposition (41 patients), symptomatic epidural hematoma (27 patients), and inadequate decompression (37 patients). Screw malposition was the most common complication, with an incidence rate of 0.82%. Screw instrumentation was significantly associated with revision surgery (p = 0.023), which suggests that this procedure carried a greater risk of requiring revision. The mean time interval to reoperation for epidural hematomas was significantly shorter than the intervals for other causes of revision spinal surgery (p < 0.001), which suggests that epidural hematoma was more emergent than other complications. Also, 25.93% of patients who underwent hematoma removal experienced residual sequelae; this percentage was significantly higher than for other surgical causes of revision spinal surgery (p = 0.013). CONCLUSIONS: The results suggest that to avoid the need for reoperation, screw malposition, inadequate decompression, and epidural hematoma are the key surgical complications to be guarded against. Accordingly, adequate decompression, epidural hematoma prevention, and proper pedicle screw placement may help reduce the incidence of revision surgery.

The fusion rate of demineralized bone matrix compared with autogenous iliac bone graft for long multi-segment posterolateral spinal fusion.

BACKGROUND: Although autogenous iliac bone graft (AIBG) remains the gold standard for spine fusion, harvesting morbidity has prompted the search for alternatives especially for multi-segment fusion. This study aimed to evaluate the efficacy of using demineralized bone matrix (DBM) as a substitute of AIBG for long instrumented posterolateral fusion (≧ three-level fusion). METHODS: A total of 47 consecutive patients underwent laminectomy decompression, and multi-level instrumented posterolateral fusions were reviewed. Group 1 comprised 26 patients having DBM with autologous laminectomy bone (ALB). Group 2 consisted of 21 patients having AIBG with ALB. The fusion success evaluation was based on findings using the 12-month anteroposterior and dynamic plain radiographs. RESULTS: Gender, age, and the number of fusion levels were similar for both groups. 21 of 26 (80.8%) patients in group 1 and 18 of 21 (85.7%) patients in group 2 were observed to achieve solid bony fusion. There was no statistical difference in the fusion success (p = 0.72). Blood loss was significantly more in group 2 (p = 0.02). The duration of the hospital stays and operative times being longer for group 2, but the difference was not significant. CONCLUSIONS: DBM combined with ALB and osteoconductive materials is as effective as an autologous iliac bone graft with respect to long multi-segment posterolateral fusion success. DBM can be used as an effective bone graft substitute and may decrease morbidities associated with iliac bone graft harvest.

Transforaminal lumbar interbody debridement and fusion for the treatment of infective spondylodiscitis in the lumbar spine.

PURPOSE: To determine the safety and efficacy of using a single posterior approach with transforaminal lumbar interbody debridement and fusion (TLIDF) plus pedicle screws fixation in treating infective spondylodiscitis in the lumbar spine. METHODS: Between January 2009 and June 2011, 28 patients with infective spondylodiscitis who underwent TLIDF, using autogenous graft and posterior pedicle screws instrumentation, met the indications for surgery, and completed more than 18 months of follow-up, were included. Clinical outcomes were assessed using a visual analog scale (VAS), the Oswestry Disability Index (ODI), and Kirkaldy-Willis functional outcome criteria. Infection status was evaluated using C-reactive protein levels, erythrocyte sedimentation rate, and clinical symptoms. The interbody fusion status and sagittal alignment of the infected segments were assessed using radiographic studies. RESULTS: Intra-operative culture rate was 82.1 %. The most common pathogen was methicillin-resistant Staphylococcus aureus. One post-operative deep wound infection with septic implant loosening and one instance of early aseptic implant loosening were noted. Implants in both patients were subsequently removed. Two infections recurred within 3 months post-operatively, with both subsiding within 3 months after extended antibiotic treatment. VAS and ODI values were significantly improved. The interbody fusion rate was 82.1 % and the lordotic angle of the infected segments and the lumbar spine were corrected by 9.7° and 14.3°, respectively at the last follow-up. CONCLUSIONS: A single posterior approach with TLIDF and pedicle screws instrumentation for lumbar infective spondylodiscitis provided a satisfactory clinical outcome, adequate infection control and good fusion rate, and this strategy avoids the risks of anterior or staging surgeries.

Symptomatic epidural hematoma after lumbar decompression surgery.

BACKGROUND CONTEXT: Postoperative symptomatic epidural hematoma (SEH) is a serious complication of lumbar spine surgery. Despite its rarity, this uncommon complication may result in devastating neurological sequelae, including lower limb weakness. PURPOSE: A retrospective study was made to identify possible risk factors of postoperative spinal epidural hematoma by reviewing the clinical cases of this rare complication and analyzing the postoperative evaluations of patients. METHODS: From 2002 to 2010, out of 15,562 who underwent lumbar decompression procedure with/without instrumentation, 25 patients required reoperation for epidural hematoma after the initial spinal surgery. For the control group, another 75 patients were randomly selected from the pool of patients who received lumbar decompression surgery during the same period of time. The medical records of preoperative, intraoperative and postoperative factors were collected to determine possible risk factors by comparing between the cases and controls, and the postoperative evaluations of muscle power, intractable pain, saddle anesthesia, time to detection and time to evacuation were analyzed to find if there is any significant relation within the case group. Mann-Whitney U test, two-sample t test, χ (2) test and Fisher's exact test were used for statistical analysis. RESULTS: The incidence of postoperative symptomatic epidural hematoma is 0.16%. After the initial procedure, 20 (80%) patients developed progressive decrease in muscle power (MP ≤ 3), 14 (56%) patients had intractable pain (VAS ≥ 7), and 19 (76%) patients had saddle anesthesia. Preoperative diastolic blood pressure, intraoperative use of gelfoam for dura coverage and postoperative drain output were statistically significant risk factors (p < 0.01). Within the SEH case group, postoperative symptom of decreased muscle power had significant relation with blood loss, laminectomy level and fusion level (p = 0.016, 0.021, 0.010). If the symptom of decreased muscle power or perianal anesthesia was not improved after hematoma evacuation, there was a tendency for permanent leg weakness after 1-year follow-up (p = 0.001, 0.003). CONCLUSIONS: The findings suggest that preoperative diastolic blood pressure, intraoperative use of gelfoam for dura coverage and postoperative drain output are risk factors for symptomatic epidural hematoma after lumbar decompression surgery. Major blood loss and multilevel surgical procedure could result in poor recovery of muscle power. After spine decompression surgery, early detection and evacuation of hematoma are the key to avoid neurologic deterioration and have better clinical outcomes.

Effects of low-intensity pulsed ultrasound on spinal pseudarthrosis created by nicotine administration: a model of lumbar posterolateral pseudarthrosis in rabbits.

OBJECTIVES: Low-intensity pulsed ultrasound (US) can enhance spinal fusion and fracture healing; however, its effect on spinal pseudarthrosis has not been reported in the literature. We hypothesized that low-intensity pulsed US could overcome spinal pseudarthrosis created by nicotine administration. METHODS: Thirty-two rabbits underwent posterolateral fusion with an iliac bone graft and nicotine administration. At 5 weeks, the spines were examined by computed tomography (CT) to determine the presence of pseudarthrosis. All rabbits with pseudarthrosis were randomly divided into groups A, B, C, and D according to treatment: no second graft, iliac autograft only, low-intensity pulsed US only, and iliac autograft and low-intensity pulsed US, respectively. At 10 weeks, the rabbits were euthanized, and the specimens were assessed with radiography, CT, manual palpation, and histologic analysis. RESULTS: One rabbit was lost because of severe infection. Twenty-seven (87%) had pseudarthrosis on CT at 5 weeks. On manual palpation at 10 weeks, the fusion rates were 0%, 29%, 0%, and 57% in groups A, B, C, and D, respectively. Group D had highest radiographic scores (mean ± SD, 2.87 ± 0.92), and the difference was statistically significant compared to the other groups (P < .001). Computed tomography confirmed that group D had the most fused segments at 10 weeks. Histologic specimens from group D also showed the most mature bone formation inside the fusion mass. CONCLUSIONS: Low-intensity pulsed US can enhance spinal fusion but cannot overcome spinal pseudarthrosis created by nicotine administration. Stopping nicotine consumption or administering a more powerful bone substitute might be an alternative method for overcoming spinal pseudarthrosis.

Combined anterior lumbar interbody fusion and instrumented posterolateral fusion for degenerative lumbar scoliosis: indication and surgical outcomes.

BACKGROUND: Traditional approaches to deformity correction of degenerative lumbar scoliosis include anterior-posterior approaches and posterior-only approaches. Most patients are treated with posterior-only approaches because the high complication rate of anterior approach. Our purpose is to compare and assess outcomes of combined anterior lumbar interbody fusion and instrumented posterolateral fusion with posterior alone approach for degenerative lumbar scoliosis with spinal stenosis. METHODS: Between November 2002 and November 2011, a total of 110 patients with degenerative spinal deformity and curves measuring over 30° were included. Of the 110 patients who underwent surgery, 56 underwent the combined anterior and posterior approach and 54 underwent posterior surgery at our institution. The following were the indications of anterior lumbar interbody fusion: (1) rigid or frank lumbar kyphosis, (2) anterior or lateral bridged traction osteophytes, (3) gross coronal and sagittal deformity or imbalance, and (4) severe disc space narrowing that is not identifiable when performing posterior or transforaminal lumbar interbody fusion. The clinical outcomes were evaluated using the Oswestry disability index and the visual analog scale. The status of fusion were assessed according to the radiographic findings. RESULTS: All patients received clinical and radiographic follow-up for a minimum of 24 months, with an average follow-up of 53 months (range, 26-96 months). At the final follow-up, the mean ODI score improved from 28.8 to 6.4, and the mean back/leg VAS, from 8.2/5.5 to 2.1/0.9 in AP group and the mean ODI score improved from 29.1 to 6.2, and the mean back/leg VAS, from 9.0/6.5 to 2.3/0.5 in P group. The mean scoliotic angle changed from 41.3° preoperatively to 9.3°, and the lumbar lordotic angle, from 3.1° preoperatively to 35.7° in AP group and the mean scoliotic angle from 38.5 to 21.4 and the lumbar lordotic angle from 6 to 15.8 in P group. There were significant differences in sagittal (P = 0.009) and coronal (P = 0.02) plane correction between the two groups. CONCLUSIONS: Our results demonstrate that combined anterior lumbar interbody fusion and instrumented posterolateral fusion for adult degenerative lumbar scoliosis effectively improves sagittal and coronal plane alignment than posterior group and both group were effectively improves clinical scores.

Postoperative meningitis after spinal surgery: a review of 21 cases from 20,178 patients.

BACKGROUND: Postoperative bacterial meningitis is a rare complication of spinal surgery and is considered to be a complication related to intraoperative incidental durotomy. A high index of suspicion for meningitis is essential in patients who have the clinical triad of fever, neck stiffness and consciousness disturbance during the postoperative period. A delay in diagnosis or treatment can lead to morbidity and mortality. Due to the low incidence of postoperative meningitis, very few studies have reported this complication. The purpose of this study was to report the clinical features, laboratory evaluations, treatment course and prognosis of 21 patients with post spinal surgery meningitis. METHODS: We retrospectively reviewed 21 patients (13 male, 8 female) with the diagnosis of postoperative meningitis after lumbar spinal surgery between January 2001 and Aug 2011. The median age of the patients was 67 years old (range 27 to 82 years) at the time of surgery. We recorded the preoperative diagnosis, operative methods, amount of drainage, clinical manifestations, laboratory evaluations, cerebrospinal fluid study, and infectious organisms. All patients diagnosed with postoperative meningitis received at least two weeks of antibiotic treatment. Clinical outcomes were assessed after at least two years of follow-up. RESULTS: From January 2001 to August 2011, 20,178 spinal operations were performed in our institution, and 21 patients (0.10%) were diagnosed with postoperative meningitis. Eighteen patients (85.7%) had fever, 19 (90.5%) had neck stiffness, and 16 (76.2%) had consciousness disturbance. All patients had at least two of the classic triad. In addition, 9 patients (42.9%) had headache, 3 (14.3%) had focal neurological deficits, and 2 (9.5%) had seizure attacks. There was no mortality in this series. Postoperative meningitis showed no adverse effect on the results of spinal surgery after follow-up for at least two years. CONCLUSIONS: Postoperative meningitis is a rare complication after spinal lumbar surgery. A high index of suspicion for meningitis should be maintained in patients with the clinical triad of fever, neck stiffness, and consciousness disturbance after spinal surgery. Intraoperative incidental durotomy is the most important predictor. An early diagnosis and appropriate antibiotic treatment can lead to a good outcome.

Extended indications of percutaneous endoscopic lavage and drainage for the treatment of lumbar infectious spondylitis.

PURPOSE: The treatment of spinal infection remains a challenge for spinal surgeons because of the variable presentations and complicated course. The diagnostic and therapeutic value of percutaneous endoscopic lavage and drainage (PELD) has been proved in some recent studies. The purpose of this study is to evaluate the efficacy of PELD in patients with advanced infectious spondylitis which may traditionally require open surgery. METHODS: We retrospectively reviewed the medical records of 21 patients who underwent PELD to treat their advanced lumbar infectious spondylitis. Patients with severe infection resulting in significant neurological deficit and mechanical instability were excluded from the PELD procedure, which was only used on selected patients with less severe disease. The 21 patients were categorized into three groups based on their past history, clinical presentation, and imaging studies: those with paraspinal abscesses, postoperative recurrent infection, and multilevel infection. Clinical outcomes were assessed by careful physical examination, Odom's criteria, regular serologic testing, and imaging studies to determine whether continued conservative treatment or surgical intervention was necessary. RESULTS: Causative bacteria were identified in 19 (90.5%) of 21 biopsy specimens. Appropriate parenteral antibiotics for the predominant pathogen isolated from the infected tissue biopsy cultures were prescribed for the patients. All patients reported satisfactory recovery and relief of back pain, except three with multilevel infections who underwent anterior debridement and fusion within 2 weeks after treatment with PELD. The overall infection control rate was 86%. One patient with epidural abscess and spondylolytic spondylolisthesis of the L5-S1 received instrumented fusion surgery due to mechanical instability 5 months later. No surgery-related major complications were found, except 2 patients who had transient paraesthesia in the affected lumbar segment. CONCLUSIONS: PELD was successful in obtaining a bacteriologic diagnosis, relieving the patient's symptoms, and assisting in eradication of lumbar infectious spondylitis. The indications of this minimally invasive procedure could be extended to treat patients suffering from spinal infections with paraspinal abscesses and postoperative recurrent infection. Patients with multilevel infection may have trivial benefits from PELD due to poor infection control and mechanical instability of the affected segments.