Degenerative cervical myelopathy presenting as subjective lower limb weakness could be a trap towards misdiagnosis.

When patients presenting with subjective lower limb weakness (SLLW) are encountered, it is natural to suspect a lumbar pathology and proceed with related clinical examination, investigations and management. However, SLLW could be a sign of degenerative cervical myelopathy (DCM) due to an evolving cord compression. In such circumstances, if symptoms are not correlated to myelopathy at the earliest, there could be potential complications over time. In this study, we intend to analyse the outcomes after surgical management of the cervical or thoracic cord compression in patients with SLLW. Retrospectively, patients who presented to our center during the years 2010-2016 with sole complaint of bilateral SLLW but radiologically diagnosed to have a solitary cervical or thoracic stenosis, or tandem spinal stenosis and underwent surgical decompression procedures were selected. Their clinical presentation was categorised into three types, myelopathy was graded using Nurick's grading and JOA scoring; in addition, their lower limb functional status was assessed using the lower extremity functional scale (LEFS). Functional recovery following surgery was assessed at 6 weeks, 3 months, 6 months, one year, and two years. Selected patients (n = 24; Age, 56.4 ± 10.1 years; range 32-78 years) had SLLW for a period of 6.4 ± 3.2 months (range 2-13 months). Their preoperative JOA score was 11.3 ± 1.8 (range 7-15), and LEFS was 34.4 ± 7.7 (range 20-46). Radiological evidence of a solitary cervical lesion and tandem spinal stenosis was found in 6 and 18 patients respectively. Patients gradually recovered after surgical decompression with LEFS 59.8 ± 2.7 (range 56-65) at 1 year and JOA score 13.6 ± 2.7 (range - 17 to 100) at 2 years. The recovery rate at final follow up was 47.5%. Our results indicate the importance of clinically suspecting SLLW as an early non-specific sign of DCM to avoid misdiagnosis, especially in patients without conventional upper motor neuron signs. In such cases, surgical management of the cord compression resulted in significant functional recovery and halted the progression towards permanent disability.

Biomechanical comparison of pedicle screw fixation strength in synthetic bones: Effects of screw shape, core/thread profile and cement augmentation.

Pedicle screw loosening resulting from insufficient bone-screw interfacial holding power is not uncommon. The screw shape and thread profile are considered important factors of the screw fixation strength. This work investigated the difference in pullout strength between conical and cylindrical screws with three different thread designs. The effects of the thread profiles on the screw fixation strength of cannulated screws with or without cement augmentation in osteoporotic bone were also evaluated. Commercially available artificial standard L4 vertebrae and low-density polyurethane foam blocks were used as substitutes for healthy vertebrae and osteoporotic bones, respectively. The screw pullout strengths of nine screw systems were investigated (six in each). These systems included the combination of three different screw shapes (solid/cylindrical, solid/conical and cannulated/cylindrical) with three different thread profiles (fine-thread, coarse-thread and dual-core/dual-thread). Solid screws were designed for the cementless screw fixation of vertebrae using the standard samples, whereas cannulated screws were designed for the cemented screw fixation of osteoporotic bone using low-density test blocks. Following specimen preparation, a screw pullout test was conducted using a material test machine, and the maximal screw pullout strength was compared among the groups. This study demonstrated that, in healthy vertebrae, both the conical and dual-core/dual-thread designs can improve pullout strength. A combination of the conical and dual-core/dual-thread designs may achieve optimal postoperative screw stability. However, in osteoporotic bone, the thread profile have little impact on the screw fixation strength when pedicle screws are fixed with cement augmentation. Cement augmentation is the most important factor contributing to screw pullout fixation strength as compared to screw designs.

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

The authors would like to acknowledge the following funding information that was missing in.

Risk factors of neurological deficit and pulmonary cement embolism after percutaneous vertebroplasty.

BACKGROUND: The risk factors, incidence, and clinical management of pulmonary cement embolism and neurological deficit during percutaneous vertebroplasty (PVP) were evaluated. METHODS: Three thousand one hundred and seventy-five patients with symptomatic osteoporotic vertebral compression fractures (OVCFs) treated with PVP were retrospectively reviewed in a single institution. Clinical parameters such as age, gender, number of fractures, and time from fracture to vertebroplasty were recorded at the time of surgery. Image and surgical parameters including the amount of cement, the vertebral level, uni- or bipedicle surgical approach, and leakage pattern were recorded. RESULTS: Type-C leakage, including paraspinal (25%), intradiscal (26%), and posterior (0.7%) leakage, was more common than type-B (11.4%) and type-S leaks (4.9%). Cement leakage into the spinal canal (type-C posterior) occurred in 26 patients (0.7%), and four patients needed surgical decompression. Three in nine patients with leakage into thoracic spine needed decompressive surgery, but only one of 17 patients into lumbar spine needed surgery (p < 0.01). Age, gender, number of fractures, and time from fracture to vertebroplasty were not risk factors of pulmonary cement embolism or neurological deficit. The risk factor of pulmonary cement embolism was higher volume of PMMA injected (p < 0.001) and risk factor of neurological deficit was type-C posterior cement leakage into thoracic spine. The incidence of pulmonary cement embolism was significantly high in the volume of PMMA injected (PMMA injection < 3.5 cc: 0%; 3.5-7.0 cc: 0.11%; > 7.0 cc: 0.9%; p < 0.01) which needed postoperative oxygen support. CONCLUSIONS: Cement leakage is relatively common but mostly of no clinical significance. Percutaneous vertebroplasty in thoracic spine and high amount of PMMA injected should be treated with caution in clinical practice.

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.

Transforaminal Interbody Debridement and Fusion to Manage Postdiscectomy Discitis in Lumbar Spine.

BACKGROUND: Traditionally, nonoperative management with long-term antibiotics and bed rest has been recommended as first-line treatment for most patients with postoperative discitis. A recent trend in treatment under a limited range of indications has been to perform surgical débridement followed by long-term administration of antibiotics. This descriptive study investigated whether transforaminal lumbar interbody débridement and fusion (TLIDF) combined with intravenous antibiotics is appropriate to manage postdiscectomy discitis. METHODS: This study retrospectively analyzed demographic data, laboratory data, and radiography and magnetic resonance imaging of 10 patients with postoperative discitis who underwent surgical TLIDF followed by antibiotic treatment. Preoperative and postoperative spine sagittal alignment, visual analog scale scores, and Kirkaldy-Willis criteria for functional outcomes were evaluated. RESULTS: An infection clearance rate of 100% was ultimately achieved for the patients who underwent TLIDF with short posterior instrumentation. TLIDF yielded better outcomes than traditional conservative treatment in terms of spine alignment correction, functional outcomes, and quality of life. CONCLUSIONS: Based on previously reported data and the findings of this study, we suggest that surgical intervention should be used in certain cases, as it can achieve better outcomes than conservative treatment. We recommend a novel single posterior approach with TLIDF and posterior pedicle screw instrumentation for management of postdiscectomy discitis.

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.

Factors related to post surgical neurologic improvement for cervical spine infection.

BACKGROUND: Cervical spine infections are uncommon but potentially dangerous, having the highest rate of neurological compromise and resulting disability. However, the factors related to surgical success is multiple yet unclear. METHODS: We retrospectively reviewed the medical records of 27 patients (16 men and 11 women) with cervical spine infection who underwent surgical treatment at Chang Gung Memorial Hospital, Linkou branch, between 2001 and 2014. The neurological status, by Frankel classification, was recorded preoperatively and at discharge. Group X had neurologic improvement of at least 1 grade, group Y had unchanged neurologic status, and group Z showed deterioration. We recorded the patient demographic data, presenting symptoms and signs, interval from admission to surgery, surgical procedure, laboratory data, perioperative antibiotic course, pathogens identified, coexisting medical disease, concomitant nonspinal infection, and clinical outcomes. We intended to evaluate the different characteristics of patients who improved neurologically after treatment. RESULTS: The mean age of our cohort was 56.6 years. Anterior cervical discectomy and fusion was the most commonly performed surgical procedure (74.1%). The Frankel neurological status improved in 70.4% (group X, n = 19) and unchanged in 29.6% (group Y, n = 8). No patients worsened. Motor weakness was most common (96.3%) neurological deficit, followed by sensory abnormalities (37.0%), and bowel/urine incontinence (33.3%). The main difference in presentation between group X and group Y was neck pain (100% vs. 75.0%; p = .02), not fever. Group X had a shorter preoperative antibiotic course (p = .004), interval from admission to operation (p = .02), and hospital stay (p = .01). CONCLUSION: Clinicians should be more suspicious in patients who present with neck pain and any neurological involvement even in those without fever while establishing early diagnosis. Earlier operative treatment in group X result in better neurologic recovery and shorter hospital stay due to disease improvement.

Appropriate duration of post-surgical intravenous antibiotic therapy for pyogenic spondylodiscitis.

BACKGROUND: Most guidelines recommend 6 to 12 weeks of parenteral antibiotic treatment for pyogenic spondylodiscitis. When surgical debridement is adequately performed, further intravenous antibiotic treatment duration can be reduced than that of conservative treatment alone theoretically. However, the appropriate duration of post-surgical parenteral antibiotic treatment is still unknown. This study aimed to identify the risk factors of recurrence and evaluate the appropriate duration after surgical intervention. METHODS: This 3-year retrospective review included 102 consecutive patients who were diagnosed with pyogenic spondylodiscitis and underwent surgical intervention. Recurrence was defined as recurrent signs and symptoms and the need for another unplanned parenteral antibiotic treatment or operation within one year. This study included two major portions. First, independent risk factors for recurrence were identified by multivariable analysis, using the database of demographic information, pre-operative clinical signs and symptoms, underlying illness, radiographic findings, laboratory tests, intraoperative culture results, and treatment. Patients with any one of the risk factors were considered high-risk; those with no risk factors were considered low-risk. Recurrence rates after short-term (≤3 weeks) and long-term (> 3 weeks) parenteral antibiotic treatment were compared between the groups. RESULTS: Positive blood culture and paraspinal abscesses were identified as independent risk factors of recurrence. Accordingly, 59 (57.8%) patients were classified as low-risk and 43 (42.2%) as high-risk. Among the high-risk patients, a significantly higher recurrence rate occurred with short-term than with long-term antibiotic therapy (56.2% vs. 22.2%, p = 0.027). For the low-risk patients, there was no significant difference between short-term and long-term antibiotic therapy (16.0% vs. 20.6%, p = 0.461). CONCLUSIONS: The appropriate duration of parenteral antibiotic treatment in patients with pyogenic spondylodiscitis after surgical intervention could be guided by the risk factors. The duration of postoperative intravenous antibiotic therapy could be reduced to 3 weeks for patients without positive blood culture or abscess formation.

Is Convex Derotation Equally Effective as Concave Derotation for Achieving Adequate Correction of Selective Lenke's Type- 1 Scoliosis?

BACKGROUND: Correcting the scoliosis and stabilizing the spine in the corrected position is the basis of treatment for adolescent idiopathic scoliosis (AIS). Spinal instrumentation and derotation are the principle steps of surgery for any type of AIS. A perspicuous understanding needs to be attained regarding derotation maneuvers in practice; therefore, we intend to compare radiological outcomes following concave and convex rod derotation maneuvers to analyze their efficacy to correct selective Lenke's Type-1 scoliosis. MATERIALS AND METHODS: Retrospectively, 88 patients with Lenke's Type-1 scoliosis who were operated with selective thoracic instrumentation were divided into two groups depending on the derotation side. Preoperative radiographs were analyzed for curve angles, thoracic apical vertebral translation, apical vertebral rotation, and coronal/sagittal balance. Postoperative and followup assessment was focused on curve correction. Correction rate of main thoracic (MT) curve and its corresponding loss of correction at final followup are calculated. RESULTS: Concave group (n = 40; age 13.8 ± 1.9) and the convex group (n = 48; Age 14.3 ± 2.4) showed similar demographic characteristics. Postoperative and followup parameters showed no significant difference. Correction rate of MT curve between both groups (concave group = 69.2 ± 10.5%; convex group = 66 ± 12.8%; P = 0.20) was similar. There was minimal loss of correction at final followup among both groups (concave group = 2.2° ±5.4°; Convex group = 1.5° ± 4.8°; P = 0.52). CONCLUSION: The study results showed similar sustained satisfactory correction of flexible Lenke's type 1 scoliotic curves irrespective of the derotation maneuver used. Adequate correction, thereby restoring balance was predominantly perceived among the entire sample. Hence, convex derotation can be considered equally effective as that of concave derotation for achieving adequate correction of selective Lenke's Type-1 scoliosis.

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.

Surgical outcome of atypical subtrochanteric and femoral fracture related to bisphosphonates use in osteoporotic patients with or without teriparatide treatment.

BACKGROUND: Atypical subtrochanteric fracture and femoral fracture have been considered to be rare complications related to long-term bisphosphonates use. A reduced bone turnover rate may lead to delayed bone healing. Limited data have revealed that teriparatide treatment may reverse the effect of bisphosphonates and be effective in bone healing. METHODS: We reviewed patients with atypical subtrochanteric and femoral fracture related to bisphosphonates use between January 2008 and December 2014. Thirteen female patients were enrolled. Radiographic findings were compatible with the characteristics of atypical fracture. Surgical intervention was performed for all, and teriparatide use was advised postoperatively. Outcome measures included perioperative results, and clinical and radiographic outcome. RESULTS: Of the 13 female patients enrolled, 10 had subtrochanteric and 6 had proximal femoral fracture; 3 had bilateral fractures. The mean age of the patients at surgery was 70.15±6.36 years. Most fractures (68.8%) presented prodromal thigh pain. All patients were treated with an intramedullary fixation system without severe complications. The patients were divided into 2 groups based on whether they had received treatment with teriparatide or not. The mean time to bone union was 4.4 months in the teriparatide-treated group, and 6.2 months in the non-teriparatide-treated group (p=0.116). Six patients (75%) in the teriparatide-treated group and 4 (50%) in the non-teriparatide-treated group (p= 0.3) achieved bone union within 6 months. The means of the modified Harris Hip Score and Numerical Rating Scale were significantly better in the teriparatide-treated group at postoperative 6 months. Seven patients had the same ability to walk at the 1-year follow-up as they did before the atypical fracture. CONCLUSIONS: Teriparatide treatment in patients with atypical fracture may help in fracture healing, hip function recovery, and pain relief in this reduced bone turnover patient group.

One-stage posterior approaches for treatment of thoracic spinal infection: Transforaminal and costotransversectomy, compared with anterior approach with posterior instrumentation.

Treating thoracic infective spondylodiscitis with anterior surgical approaches carry a relatively high risk of perioperative and postoperative complications. Posterior approaches have been reported to result in lower complication rates than anterior procedures, but more evidence is needed to demonstrate the safety and efficacy of 1-stage posterior approaches for treating infectious thoracic spondylodiscitis.Preoperative and postoperative clinical data, of 18 patients who underwent 2 types of 1-stage posterior procedures, costotransversectomy and transforaminal thoracic interbody debridement and fusion and 7 patients who underwent anterior debridement and reconstruction with posterior instrumentation, were retrospectively assessed.The clinical outcomes of patients treated with 1-stage posterior approaches were generally good, with good infection control, back pain relief, kyphotic angle correction, and either partial or solid union for fusion status. Furthermore, they achieved shorter surgical time, fewer postoperative complications, and shorter hospital stay than the patients underwent anterior debridement with posterior instrumentation.The results suggested that treating thoracic spondylodiscitis with a single-stage posterior approach might prevent postoperative complications and avoid respiratory problems associated with anterior approaches. Single-stage posterior approaches would be recommended for thoracic spine infection, especially for patients with medical comorbidities.

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.

Additional vertebral augmentation with posterior instrumentation for unstable thoracolumbar burst fractures.

BACKGROUND: To investigate the role of vertebral augmentation in kyphosis reduction, vertebral fracture union, and correction loss after surgical management of thoracolumbar burst fracture. DESIGN: Retrospective chart and radiographic review. SETTING: Level 1 trauma center. METHODS: The analysis included patients treated between April 2007 and June 2015, who received pedicle-screw-rod distraction and reduction within two days following acute traumatic thoracolumbar burst fracture with a load sharing score >6. Medical records were retrospectively reviewed for data regarding operative details, imaging and laboratory findings, neurological function, and functional outcomes. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Sagittal index, pain score, loss of correction, and implant failure rate. RESULTS: Nineteen patients were enrolled in this study (mean age, 37.2±13years; age range, 17-62 years; female/male ratio: 10/9). Of the five patients who received only reduction (no augmentation), one underwent revision surgery because of implant failure and pedicle screw backing out. Compared to patients who received only reduction, those who received both reduction and augmentation showed better sagittal alignment after the operation, with better sagittal index immediately postoperatively and during the follow-up (p<0.05). CONCLUSIONS: Transpedicular vertebral augmentation with calcium sulfate/phosphate-based bone cement may reinforce thoracolumbar burst fracture stability, partially restore vertebral body height, and reduce pedicle screw bending and movement, thereby preventing early implant failure and late loss of correction, especially in patients with excellent fracture reduction. LEVEL OF EVIDENCE: Therapeutic level III, retrospective chart review.

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.

Pedicle screw versus hybrid posterior instrumentation for dystrophic neurofibromatosis scoliosis.

Surgical management of severe rigid dystrophic neurofibromatosis (NF) scoliosis is technically demanding and produces varying results. In the current study, we reviewed 9 patients who were treated with combined anterior and posterior fusion using different types of instrumentation (i.e., pedicle screw, hybrid, and all-hook constructs) at our institute.Between September 2001 and July 2010 at our institute, 9 patients received anterior release/fusion and posterior fusion with different types of instrumentation, including a pedicle screw construct (n = 5), a hybrid construct (n = 3), and an all-hook construct (n = 1). We compared the pedicle screw group with the hybrid group to analyze differences in preoperative curve angle, immediate postoperative curve reduction, and latest follow-up curve angle.The mean follow-up period was 9.5 ±â€Š2.9 years. The average age at surgery was 10.3 ±â€Š3.9 years. The average preoperative scoliosis curve was 61.3 ±â€Š13.8°, and the average preoperative kyphosis curve was 39.8 ±â€Š19.7°. The average postoperative scoliosis and kyphosis curves were 29.7 ±â€Š10.7° and 21.0 ±â€Š13.5°, respectively. The most recent follow-up scoliosis and kyphosis curves were 43.4 ±â€Š17.3° and 29.4 ±â€Š18.9°, respectively. There was no significant difference in the correction angle (either coronal or sagittal), and there was no significant difference in the loss of sagittal correction between the pedicle screw construct group and the hybrid construct group. However, the patients who received pedicle screw constructs had significantly less loss of coronal correction (P < .05). Two patients with posterior instrumentation, one with an all-hook construct and the other with a hybrid construct, required surgical revision because of progression of deformity.It is difficult to intraoperatively correct dystrophic deformity and to maintain this correction after surgery. Combined anterior release/fusion and posterior fusion using either a pedicle screw construct or a hybrid construct provide similar curve corrections both sagittally and coronally. After long-term follow-up, sagittal correction was maintained with both constructs. However, patients treated with posterior instrumentation using pedicle screw constructs had significantly less loss of coronal correction.

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.

Characterization of a novel caudal vertebral interbody fusion in a rat tail model: An implication for future material and mechanical testing.

BACKGROUND: Of the proposed animal interbody fusion models, rat caudal discs have gained popularity in disc research due to their strong resemblance to human discs with respect to geometry, composition and mechanical properties. The purpose of this study is to demonstrate an efficient, repeatable and easily accessible animal model of interbody fusion for future research into mechanical testing and graft materials. METHODS: Twelve 12-week-old female Sprague-Dawley (SD) rats underwent caudal interbody fusion of the third and fourth coccygeal vertebrae of the tail. Serial radiological evaluation, and histological evaluation and manual palpation after sacrifice were performed to assess the fusion quality. Mechanical testing of functional units (FUs) of non-operated and operated segments was compared using a three-point bending test. RESULTS: At postoperative 12 weeks, callus formation was observed at the fusion sites in all rats, with the mean radiological evaluations of 2.75/3 according to the Bransford classification. Newly formed bone tissue was also observed in all rats with the mean histological score of 5.85/7, according to the Emery grading system. No palpable gaps and obvious change of bending stiffness was observed in the operated segments. The mean bending stiffness of the FUs was statistically higher than that of the control FUs (26.57 ± 6.71 N/mm vs. 12.45 ± 3.21 N/mm, p < 0.01). CONCLUSION: The rat caudal disc interbody fusion model proved to be an efficient, repeatable and easily accessible model. Future research into adjuvant treatments like growth factor injection and alternative fusion materials under conditions of osteoporosis using this model would be worthwhile.

Retrospective radiological outcome analysis following teriparatide use in elderly patients undergoing multilevel instrumented lumbar fusion surgery.

Elderly patients with chronic nonresolving symptoms due to degenerative spine pathologies are prone to have poor surgical outcomes and hardware-related complications, especially following multilevel instrumented lumbar fusion surgeries. With intention of analyzing if teriparatide can be an effective adjunct therapy to surgical management, radiological outcomes are studied. Sixty-two elderly patients were divided into 2 similar groups. Group 1 (n = 30; mean age = 69.83 years; fusion levels = 137; screws = 269) had taken teriparatide (20 mcg SC injection, once daily) for a duration of 7.4 ±â€Š2.4 months following surgery and Group 2 (n = 32; mean age = 70.38 years; fusion levels = 144; screws = 283) did not take teriparatide. Radiological evaluation was done to determine the state of postero lateral fusion mass and to investigate the incidence of pedicle screw loosening at 1-year follow-up. Unilateral or bilateral bridging bone formation across the transverse process of adjacent vertebras showing continuous trabeculation suggestive of solid fusion was obtained in 66.7% patients in the teriparatide group and 50% patients in the control group (P = 0.20). 13.4% of the total no. of screws showed signs of loosening in the teriparatide group, compared to 24.4% in the control group (P = 0.001). Percentage of patients achieving solid fusion following teriparatide use was found to be more than that of the control group. This difference may have clinical importance but was not statistically significant. However, teriparatide use was more significantly influential in reducing the incidence of subsequent pedicle screw loosening.