Mobile cauda equina ependymoma, case report and literature review.

The aim of this study was to describe a very rare presentation of ependymoma that can derive from intraoperative complications for surgeons and increased morbidity for the patients. Multiple cases of mobile cauda equina tumors leading to inadequate approach have been reported in the literature, however, the reports of ependymoma histology are very rare. This report describes the third adult case in recent years and a retrospective review of cases reported in the literature until today. We show the clinical and radiographic presentation of a 79 years old patient that presented a mobile cauda equina tumor in the preoperative image, who went to surgery for resection and arthrodesis, obtaining in post-operative histology the diagnostic of ependymoma. The preoperative image shows the migration of the tumor avoiding the wrong approach. The patient went to surgery for laminectomy, pedicular screw arthrodesis L1-S1, and tumor removal, obtaining a complete resection and confirmed histology diagnostic of ependymoma, unfortunately, the patient died five days after by a cardiac arrest. The recent literature reports only four cases of mobile ependymoma, two of them in pediatrics patients and just only two adult cases, which means this is the third adult case of an ependymoma. Mobile cauda equina ependymoma is a very rare neoplasm presentation but is an entity that can lead to mistakes in the approach and may be useful for the neurosurgeons who day per day treat this pathology beware of this possibility.

Does Navigation Improve Pedicle Screw Placement Accuracy? Comparison Between Navigated and Non-navigated Percutaneous and Open Fixations.

BACKGROUND: The aim of our study was to assess how a preoperative computed tomography (CT)-based navigation system affected the correctness and safety of transpedicular screw insertion, compared with standard techniques. METHOD: Between January 2012 and February 2014, 203 patients underwent thoracic and lumbar fixation, with open and percutaneous techniques; 218 screws were implanted through an open navigated technique (1.0 Spine & Trauma 3d ver. 2.0 BrainLab, Feldkirchen Germany) in 43 patients; 220 screws were inserted with an open free-hand technique in 45 patients; 230 screws were implanted in 56 patients using percutaneous CT-based navigation; and 236 screws were inserted in 59 patients using a percutaneous fluoroscopy-guided technique. To our knowledge, this is the first work comparing these four different techniques. The position of each screw was evaluated on CT scan reconstruction and classified according to a four-point grading scale (grade 0: no breach, grade 1: breach < 2 mm, grade 2: breach between 2 and 4 mm; grade 3: breach >4 mm). Statistical analysis was assessed by two-way analysis of variance (ANOVA) t test, while the Fisher least significant difference (LSD) method was employed to determine statistical significance. RESULTS: Statistical analysis showed a significant difference in accuracy between the open CT-based navigation and the percutaneous CT-based navigation techniques (P= 0.0263) and between the open CT-based navigation and the percutaneous fluoroscopy-guided techniques (P=0.0258): a particular difference was observed in anterior misplacement between open CT-based navigation and the percutaneous fluoroscopy-guided technique (P= 0.0153). CONCLUSIONS: Our results confirm the advantages of the navigation technique, which ensures greater accuracy, in open as well as percutaneous procedures.

Short isthmic versus long trans-isthmic C2 screw: anatomical and biomechanical evaluation.

INTRODUCTION: The Harms technique is now considered as the gold standard to stabilize C1-C2 cervical spine. It has been reported to decrease the risk of vertebral artery injury. However, the risk of vascular injury does not totally disappear, particularly due to the proximity of the trans-isthmic C2 screw with the foramen transversarium of C2. In order to decrease this risk of vertebral artery injury, it has been proposed to use a shorter screw which stops before the foramen transversarium. OBJECT: The main objective was to compare the pull-out strength of long trans-isthmic screw (LS) versus short isthmic screw (SS) C2 screw. An additional morphological study was also performed. METHOD: Thirteen fresh-frozen human cadaveric cervical spines were included in the study. Orientation, width and height of the isthmus of C2 were measured on CT scan. Then, 3.5-mm titanium screws were inserted in C2 isthmus according to the Harms technique. Each specimen received a LS and a SS. The side and the order of placement were determined with a randomization table. Pull-out strengths and stiffness were evaluated with a testing machine, and paired samples were compared using Wilcoxon signed-rank test and also the Kaplan-Meier method. RESULTS: The mean isthmus transversal orientation was 20° ± 6°. The mean width of C2 isthmus was less than 3.5 mm in 35 % of the cases. The mean pull-out strength for LS was 340 ± 85 versus 213 ± 104 N for SS (p = 0.004). The mean stiffness for the LS was 144 ± 40 and 97 ± 54 N/mm for the SS (p = 0.02). DISCUSSION: The pull-out strength of trans-isthmic C2 screws was significantly higher (60 % additional pull-out resistance) than SSs. Although associated with an inferior resistance, SSs may be used in case of narrow isthmus which contraindicates 3.5-mm screw insertion but does not represent the first option for C2 instrumentation. LEVEL OF EVIDENCE: Level V.

Let's think beyond the pedicle: A biomechanical study of a new conceptual extra pedicular screw and hook construct.

Background: Transpedicular screws have proven the test of time, yet they are not devoid of complications. Many newer techniques such as 2 D and 3D fluoroscopy,O arm Navigation assisted surgery, robotic assisted surgery have come into existence to the increase precision in pedicle screw insertion. But, complications do occur in their presence. We propose an Extra pedicular screw and hook system (EPSH) system with similar biomechanical property, better safety profile and short learning curve compared to traditional pedicle screw. Purpose: To Compare the pull out strength of Traditional Pedicle screw Vs Extra pedicular screw and hook system(EPSH). Methods: Biomechanical testing was conducted according ASTM F543 guidelines to compare the pull-out strength of EPSH based construct and traditional pedicle screw construct. Six saw bone samples in each group considered. Screw of 5.5 mm diameter and length of 35 mm was used in both the groups. Pull out strength assessed by giving 5 mm/min axial load. The axial load Vs displacement of the screw were recorded and plotted. The maximum load required for screw failure is noted in both the group. Statistical analysis was done. Results: The mean peak load of pedicle screw group was found to be 1670.9 ± 393.2 N with mean displacement at peak load was found to be 13.44 ± 1.7 mm and in EPSH group it was 1416.4 ± 341.4 N and 15.78 ± 3.9 mm respectively. A paired t-test showed no statistical difference(p < 0.05) between 2 groups. Conclusion: EPSH has shown to have almost similar biomechanical property as that pedicle screw construct. With Addition of the hook, it provides an extra rotational stability as well. Being an extra-pedicular screw it has high safety profile and needs less expertise for insertion.

Posterior hinge fixation for the treatment of unstable traumatic sacroiliac joint injuries.

INTRODUCTION: Posterior hinge fixation (PHF) is a sacroiliac joint fixation method indicated for the surgical treatment of unstable pelvic ring fractures (tile C). HYPOTHESIS: PHF yields good functional outcomes based on the Majeed score at more than 1 year of follow-up. METHODS: A single-center, retrospective study of patients who had a Tile C pelvic ring fracture, who were operated by PHF and who were evaluated at a minimum follow-up of 1 year. The functional outcome was determined using the Majeed score and pain was evaluated by the patients using a visual analog scale (VAS). The preoperative, intraoperative and postoperative data, complications and sequelae were documented. A CT-scan was done at least 1 year after the surgical treatment to determine the SI joint's reduction and fusion. RESULTS: Included were 22 patients (59% men) who had a mean age of 37.3±11.9 years; 21 of these patients were reviewed at a mean of 4.8±4 years. The mean Majeed score at the final assessment was 76.4 points±15.3, with 24% of patients having excellent results (n=5), 53% having good results (n=11), 19% having average results (n=4) and 5% having poor results (n=1). The mean pain level on VAS was 28±23mm. Of the eight surgical site infections, seven occurred in the PHF (88%). CT-scans taken at 1 year postoperative were compared to the preoperative scans. The pelvic opening was reduced by -9±6 (p<0.01), SI diastasis by -11mm±9 (p<0.001), vertical displacement by-7mm±8 (p<0.001), symphysis opening by -15mm±15 (p<0.001), median transverse diameter by -10mm±9 (p<0.001) and bispinal diameter by -5mm±7 (p<0.001). SI fusion was confirmed in 43% of patients (n=9). CONCLUSION: PHF is a surgical instrumentation method that provides satisfactory long-term reduction of Tile C pelvic ring fractures. The clinical outcomes are good or excellent in 77% of cases. The perioperative morbidity is marked by surgical site infections, all of which healed. LEVEL OF EVIDENCE: IV; retrospective, non-comparative cohort study.

A morphometric analysis of thoracolumbar vertebrae in goat by computed tomography.

The goat spine is widely used as an animal model for preclinical research in human medicine to test new spinal implants and surgical procedures. Therefore, precise morphometric data are needed. This study aims to provide morphometric data of the goat thoracolumbar vertebrae and to define the parameters/characteristics of the optimum implantation corridors for pedicle screws in the thoracolumbar spine in goat. Eleven 36-month-old adult alpine goats were included in this study, and a sample of 198 vertebrae was measured. Subsequently, transverse and sagittal images were obtained using a multi-detector-row helical computed tomography (CT) scanner. Measurements of the vertebral bodies (ventral body width VBW, ventral body depth VBD, ventral body height ventral VBHv, ventral body high dorsal VBHd, spinal canal depth SCD, spinal canal width SCW), pedicles (pedicle length PDL, pedicle width PDW, pedicle angle PA and pedicle axis length PAL), intervertebral disc (DT) and transverse process length (TPL) were performed with dedicated software. The vertebral bodies and the spinal canal were wider than deep, mostly evident in the lumbar region. The intervertebral discs were as much as 65.7% thicker in the lumbar spine than in the thoracic spine. The pedicles were longer than wide over the thoracic and lumbar spines. The insertion angles in pedicle were approximately 30° for the T2-T4 segment, 25° for the T5-T6 segment, 23° for the T6 to T11 segment, 20° for T11 to L3, 25° for L4 and 30° for L5 and L6. In conclusion, the generated data can serve as a CT reference for the caprine thoracolumbar spine and may be helpful in using the goat spine as an animal model for human spinal research.

Lumbar Spondylolysis Reconstruction-Stabilization Using a Motion-Preserving Technique.

BACKGROUND: Conservative methods are the traditional options in the management of lumber spondylolysis whereas surgery is indicated for symptomatic patients not responding to medical treatment and cases with a multilevel pars defect. The aim of this prospective study was to evaluate the clinical, functional, and radiologic results of using bone graft and fixation with pedicular screw-rod-laminar hook construct in treatment of lumber spondylolysis. PATIENTS AND METHODS: Between October 2017 and January 2020, 20 patients with symptomatic lumbar spondylolysis not responding to conservative treatment for more than 6 months were treated by defect reconstruction fixation using bone block autografting and pedicular screw laminar hook construct. The mean follow-up time was 12.5 ± 03.5 months. All patients were examined pre- and postoperatively and followed up clinically (pain [visual analog scale]), functionally (Oswestry Disability Index, Modified Prolo Functional Economic Scales, and Macnab criteria), and radiologically (pars defect healing). Perioperative outcomes and complications were documented. RESULTS: Clinical, radiologic, and functional outcomes were significantly improved. Bony union was evident in all patients (100%). Blood loss, operative time, and hospital stay increased in cases with a multilevel pars defect and cases with associated injuries. Two cases reported complications in this study as misplaced pedicular screw and superficial wound infection. CONCLUSIONS: Reconstruction fixation of pars defect using this construct is an effective, feasible procedure in the treatment of Lumbar spondylolysis regarding the preservation of lumbar motion and avoidance of adjacent-segment problems after fusion.

Accuracy Assessment of Freehand Pedicular Screw Placement.

BACKGROUND: The purpose of this prospective study was to determine the accuracy of pedicular screw insertion without the use of fluoroscopy. METHODS: This study was conducted on patients with spinal diseases in need of pedicular screw fixation and fusion. The included patients suffered from such conditions as vertebral fracture, spinal stenosis, kyphosis, tumor, and pelvic fractures and were managed with triangular osteosynthesis fixation. However, those with scoliosis deformity were excluded from the study. A total of 760 pedicular screws were inserted in C7 to S1 vertebrae without using fluoroscopy. The locations of the screws were assessed by means of computed tomography scan after the surgery. The data were analyzed in SPSS software (version 22) using the Chi-square test. RESULTS: Out of 387 thoracic screws and 373 lumbar screws, 65 (16.8%) and 34 (9.1%) screws perforated the pedicle wall or vertebral body, respectively. The most frequent locations of perforation in the thoracic and lumbar spine were the anterior cortex of the vertebral body and medial wall of the pedicle, respectively. Except for the perforation of the anterior vertebral body (P=0.0001), there was no difference between the left and right sides or between thoracic and lumbar sites in terms of the preformation of the screw. No complication was observed due to screw perforation. CONCLUSION: Our findings revealed the unnecessity of using fluoroscopy in spine surgeries for the insertion of pediculate screws. In this regard, the use of fluoroscopy for the placement of pedicular screw resulted in similar accuracy and complications, as compared to the free hand procedure.

Prognostic Factors for Adjacent Segment Disease After L4-L5 Lumbar Fusion.

BACKGROUND: Adjacent segment disease (ASD) is an important consideration during decision making for lumbar spinal fusion. OBJECTIVE: To identify risk factors for development of ASD after L4-L5 fusion and differences in incidence between rostral and caudal ASD. METHODS: We retrospectively reviewed all consecutive patients at a single institution who underwent first-time spinal fusion at the L4-L5 level for degenerative spinal disease over a 10-yr period, using posterolateral pedicular screw fixation with or without posterior interbody fusion. ASD was defined as clinical and radiographic evidence of degenerative spinal disease requiring reoperation at the level rostral (L3-L4) or caudal (L5-S1) to the index fusion. RESULTS: Among 131 identified patients, the incidence of ASD requiring reoperation was 25.2% (n = 33). Twenty-four cases (18.3% of the entire cohort) developed rostral ASD (segment L3-L4), 3 cases (2.3%) developed caudal (L5-S1), and 6 cases (4.6%) developed bilateral ASD (both rostral and caudal). Cumulatively, the incidence of caudal ASD was significantly lower than rostral ASD (P < .001). Following multivariate logistic regression for factors associated with ASD reoperation, decompression of segments outside the fusion construct was associated with higher ASD rates (odds ratio [OR] = 2.68, P = .039), as was female gender (OR = 3.55, P = .011), whereas older age was associated with lower ASD incidence (OR = 0.95, P = .011). CONCLUSION: When considering posterior L4-L5 fusion, surgeons should refrain from prophylactic procedures in the L5-S1 level, without clinical indications, because ASD incidence on that segment is reassuringly low.

Direct trans-pedicular screw fixation for atypical hangman's fracture: A minimally invasive technique using the tubular retractor system.

The ideal treatment strategy of atypical hangman's fracture (AHF) is debatable. If surgical treatment is needed, direct trans-pedicular fixation technique is advantageous in that it stabilizes the fracture site and spares adjacent motion segments. The authors describe relatively simple and minimally invasive technique using the tubular retractor system (TRS) for surgical treatment of AHF. Trans-pedicular screw fixation using the TRS was performed in seven patients with AHF. This technique was facilitated by using intraoperative fluoroscopy and a surgical microscope. Rigid cervical collar was used for 4 weeks, postoperatively. To evaluate postoperative radiological outcomes, cervical computed tomography (CT) was performed at postoperative 6 months. The clinical outcomes, including visual analog scale and neck motion, were evaluated. In surgical outcomes, no intraoperative neuro-vascular injury or postoperative complications occurred. For all patients, dynamic radiographs and CT images demonstrated a stable construct. Clinical examination also showed satisfactory pain relief and restoration of the full range of motion in the neck. Direct trans-pedicular screw fixation using the TRS for AHF appears to be safe and effective. This technique permits less skin incision and muscle dissection with good postoperative recovery. This report serves as a preliminary study and may be a surgical option for minimally invasive direct repair.

Straight-Forward versus Bicortical Fixation Penetrating Endplate in Lumbosacral Fixation-A Biomechanical Study.

OBJECTIVE: Many lumbosacral fixation techniques have been described to offer a more screw-bone purchase. The forward anatomical fixation parallel to the endplate is still the most preferred method. Literature revealed little knowledge regarding the mechanical stability of lumbosacral trans-endplate fixation compared to the traditional trans-pedicular screw fixation method. The aim of this study is to assess the pull-out strength of lumbosacral screws penetrating the end plate and comparing it to the conventional trans-pedicular screw insertion method. METHODS: Eight lumbar and eight sacral vertebrae, with average age 69.4 years, Left pedicles of the 5th lumbar vertebrae were used for trans-endplate screw fixation, group 1A, right pedicles were used for anatomical trans-pedicular screw fixation, group 1B. In the sacral vertebrae, the right side S1 pedicles were used for trans-endplate fixation, group 2A, left side pedicles were used for anatomical trans-pedicular screw fixation, group 2B. The biomechanical tests were performed using the axial compression testing machine. All tests were applied using 2 mm/min traction speed. RESULTS: The average pull-out strength values of groups 1A and 1B were 403.78±11.71 N and 306.26±17.55 N, respectively. A statistical significance was detected with p=0.012. The average pull-out strength values of groups 2A and 2B were 388.73±17.03 N and 299.84±17.52 N, respectively. A statistical significance was detected with p=0.012. CONCLUSION: The trans-endplate lumbosacral fixation method is a trustable fixation method with a stronger screw-bone purchase and offer a good alternative for surgeons specially in patients with osteoporosis.

Cadaveric study for ideal dorsal pedicle screw entry point.

OBJECTIVE: To determine the entry for the dorsal pedicular screw in relation to the notch present at the junction of base of the lateral margin of superior articular process with superior border of transverse process in dorsal spine. The advantage of this technique is a constant and easily identifiable entry point which does not involve partial resection of the inferior facet, thus maintaining stability and maintaining the well defined transverse and sagittal screw angles and decreasing the incidence of medial and inferior pedicle violation. MATERIALS AND METHODS: The study was carried out using ten cadavers (four male and six female). Spinal column was dissected completely from cadavers. Before the experiment, normal anatomy was confirmed on all cadavers excluding cases of spinal deformity. Dissection was done by the spine surgeons taking care to preserve all the bony landmarks near the entry point. This study was carried out bilaterally on pedicles between the first and twelfth thoracic (T) vertebrae. RESULTS: The relation of the superior articular notch and transverse process to the thoracic spine pedicles was studied. It was found that superior third of the pedicle was related to the superior articular notch and the transverse process in the first five thoracic vertebrae. The relation of these structures to the pedicle of the sixth thoracic vertebra was somewhat equally distributed between the superior and middle third of the pedicle. From the 7th to 12th thoracic vertebrae the superior articular process and transverse process were related to the middle third of the pedicle in almost all the cases. It is important to note that the inferior 1/3rd of the pedicle was not related to these landmarks at any of the levels. CONCLUSION: We conclude that the ideal pedicle entry point described here should be considered by surgeons during thoracic pedicle screw instrumentation. The notch at the base of the superior articular process will always remain constant and therefore an important anatomical landmark in guiding the screw toward the entry of the pedicle.

Lumbar segmental artery pseudoaneurysm after L5 pedicle screw placement. A rare vascular complication. / Pseudoaneurisma de arteria segmentaria lumbar tras introducción de tornillo transpedicular L5. Una rara complicación vascular.

Posterior lumbar screw fixation is a common surgical procedure nowadays. However, it can sometimes produce complications that can be devastating. One of the less common causes of major complication is the misplacement of a pedicle screw. This highlights the importance of being methodical when placing pedicle screws, and checking that the pathway has been created correctly and their placement. We present a case of a massive bleed after a pedicular screw placement during lumbar canal stenosis surgery. Screw malposition led to intraoperative haemodynamic instability after failed attempts to control bleeding in the surgical site. Contrast enhanced CT imaging revealed a lumbar intersegmentary artery injury that was eventually controlled by means of a coil embolisation.

Accuracy of minimally invasive percutaneous thoracolumbar pedicle screws using 2D fluoroscopy: a retrospective review through 3D CT analysis.

BACKGROUND: In the literature, there is a large variation in the reported misplacement rates of pedicle screws. The use of minimally invasive surgical techniques is increasing and as such there has only been a small amount of data to look at the misplacement rate of percutaneously inserted thoracic and lumbar pedicle screws. METHODS: A retrospective analysis of post-operative computed tomography (CT) scans were performed on 108 patients who underwent minimally invasive percutaneously inserted thoracic and lumbar pedicle screws by a single surgeon. Analysis of the screw trajectory using strict guidelines was performed using multiplanar reconstruction CT scan data to determine the accuracy of the pedicle screws. RESULTS: A total of 614 screws were inserted in vertebral levels T2 to S1. Twenty-five (4.07%) screws were considered misplaced having breached the pedicular cortex. Thoracic pedicle screws had a statistically higher misplacement rate than lumbar pedicle screws (14.67% vs. 2.60% respectively, P<0.001). A single screw required replacement (0.16%) and there were no permanent neurological deficits. The misplacement rates were lower than those reported for open screw placement and equivalent to 3D CT navigated misplacement rates. CONCLUSIONS: Percutaneously inserted pedicle screws using 2D fluoroscopy offers a safe and accurate option for spinal stabilisation with an extremely low misplacement rate and morbidity. Overall, the low misplacement rates were equivalent and in most cases lower compared to open and computer assisted navigation techniques. However, we would recommend that given a misplacement rate of 14.67% for thoracic pedicle screws that computer assisted navigation may be able to offer further improvements in accuracy.

Adjacent segment degeneration after posterior lumbar fusion: An analysis of possible risk factors.

OBJECTIVE: Many surveys have been distributed about the risk factors for adjacent segment degeneration (ASD) after lumbar fusion. Despite myriad of risk factors recognized for ASD evolution, study results have been inconsistent and there is not an agreement regarding which are the most important. Our study was done to identify factors which may be important in the development of symptomatic ASD after lumbar fusion. PATIENTS AND METHODS: This retrospective study evaluated 1250 consecutive patients who underwent posterior lumbar fusion and pedicular fixation between February 2006 and February 2009. A total of 13 patients with symptomatic ASD (clinical ASD) who underwent secondary surgery were identified. Another group of 22 patients without symptomatic ASD (subclinical ASD) after spinal fusion were marked as the control group. These two groups were compared for demographic data and clinical and radiographic features to investigate the possible predictive factors of symptomatic ASD. RESULTS: The overall incidence rate of symptomatic ASD was 1.04%. Radiographic risk factors for the development of a symptomatic ASD were increased sagittal balance, loss of lordosis, and adjacent disc space collapse. In the clinical ASD group, by multivariate logistic regression analysis, demonstrated that BMI, preoperative ADD on MRI and disc bulge maintained their significance in predicting likelihood of clinical ASD. CONCLUSION: Patients with increased BMI, preoperative ADD and disc bulge on MRI have a statistically significant increased risk of developing symptomatic ASD.

Pain and functional improvement effects of methylene blue injection on the soft tissue around fusion site after traumatic thoracolumbar fixation: A double-blind, randomized placebo-controlled study.

OBJECTIVE: Fractures of the thoracolumbar spine can cause pain, long-term reductions in quality of life (QOL), and neural deficits. The aim of this study was to investigate the effects of methylene blue (MB) on preventing postoperative pain and improving QOL in patients with throracolumbar fractures undergoing posterior pedicle screw fixation. METHODS: Fifty patients underwent standard posterior pedicular screw fixation for stabilization of the thoracolumbar fractures: 25 received 1ml of MB solution at a concentration of 0.5% and 25 received normal saline on the soft tissue around fusion site. Primary outcomes were the control of pain, evaluated at 48h, 2 and 6 months after surgery with the use of a visual analog scale (VAS), and the improvement of QOL, assessed 2 and 6 months postoperatively by means of Oswestry Disability Index (ODI) questionnaire. RESULTS: The mean VAS scores for pain were significantly lower in the MB group compared with the control group at 2 months (1.30±0.45 vs. 2.60±1.19, P<0.001) and 6 months (1.17±0.37 vs. 1.60±0.87; P=0.028) after treatment. At 2 months after the surgery, the mean ODI score was significantly lower in the MB-treated patients than the control group (20.4±10.92 vs. 34.8±15.11; P=0.001). The ODI score in the MB-treated patients was better than the control group at 6 months after the surgery (12.2±11.66 vs. 20.8±11.14; P=0.016). CONCLUSION: A single dose of MB on the soft tissue around fusion site shows promising results in terms of safety, reduction of postoperative pain, and functional results when compared with placebo 6 months after surgery.

Management of Unstable Thoraco-Lumbar Fractures with Pedicular Screw Instrumentation: A Series of 30 cases.

INTRODUCTION: Trauma to spine is one of the grave injuries. They cause infinite morbidity and disability to the patient. Lately consensus is evolving across the world for stabilization of unstable spines with fusion and instrumentation even though most authors agree that neurological recovery is independent of treatment modality. Objectives of this study are to evaluate effectiveness of spinal stabilization with pedicular instrumentation in the management of thoraco-lumbar fractures to restore structural stability, early ambulation and improving neurological status of the patient Material and Methods: During the period from October 2009 to September 2010, 33 cases of thoraco-lumbar spine fractures were treated operatively with posterior decompression and pedicular screw instrumentation. Of these, 3 cases were lost to follow up. Hence the results of 30 cases were evaluated. All patients were treated by posterior decompression and pedicular screw instrumentation. Neurological and radiological parameters were assessed during serial follow-ups. OBSERVATION AND RESULTS: The mean duration of follow-up was 11 months. Of the 30 patients 24 showed neurological improvement by at least 1 grade and average grade of improvement was 1.5 grades. Mean pre-operative sagittal angle (SA) was 19.9 degrees and sagittal index (SI) was 0.54. Mean post-operative SA was 9.3 degrees and SI was 0.72. Mean SA and SI during the final follow-up were 10.9 degrees and 0.69 respectively. DISCUSSION AND CONCLUSION: Neurological recovery and maintenance of radiological correction in our study were comparable to other studies. The results in our short series of 30 cases have been encouraging. But there is need for more cases and longer follow-ups to come to categorical conclusion.

Biomechanical efficacy of monoaxial or polyaxial pedicle screw and additional screw insertion at the level of fracture, in lumbar burst fracture: An experimental study.

BACKGROUND: Use of a pedicle screw at the level of fracture, also known as an intermediate screw, has been shown to improve clinical results in managing lumbar fracture, but there is a paucity of biomechanical studies to support the claim. The aim of this study was to evaluate the effect of adding intermediate pedicle screws at the level of a fracture on the stiffness of a short-segment pedicle fixation using monoaxial or polyaxial screws and to compare the strength of monoaxial and polyaxial screws in the calf spine fracture model. MATERIALS AND METHODS: Flexibility of 12 fresh-frozen calf lumbar spine specimens was evaluated in all planes. An unstable burst fracture model was created at the level of L3 by the pre-injury and dropped-mass technique. The specimens were randomly divided into monoaxial pedicle screw (MPS) and polyaxial pedicle screw (PPS) groups. Flexibility was retested without and with intermediate screws (MPSi and PPSi) placed at the level of fracture in addition to standard screws placed at L2 and L4. RESULTS: The addition of intermediate screws significantly increased the stability of the constructs, as measured by a decreased range of motion (ROM) in flexion, extension, and lateral bending in both MPS and PPS groups (P < 0.05). There was neither any significant difference in the ROM in the spines of the two groups before injury, nor a difference in the ROM between the MPSi and PPSi groups (P > 0.05), but there was a significant difference between MPS and PPS in flexion and extension in the short-segment fixation group (P < 0.05). CONCLUSIONS: The addition of intermediate screws at the level of a burst fracture significantly increased the stability of short-segment pedicle screw fixation in both the MPS and PPS groups. However, in short-segment fixation group, monoaxial pedicle screw exhibited more stability in flexion and extension than the polyaxial pedicle screw.

The change of adjacent segment and sagittal balance after thoracolumbar spine surgery.

OBJECTIVE: To characterize perioperative biomechanical changes after thoracic spine surgery. METHODS: Fifty-eight patients underwent spinal instrumented fusions and simple laminectomies on the thoracolumbar spine from April 2003 to October 2008. Patients were allocated to three groups; namely, the laminectomy without fusion group (group I, n = 17), the thoracolumbar fusion group (group II, n = 27), and the thoracic spine fusion group (group III, n = 14). Sagittal (ADS) and coronal (ADC) angles for adjacent segments were measured from two disc spaces above lesions at the upper margins, to two disc spaces below lesions at the lower margins. Sagittal (TLS) and coronal (TLC) angles of the thoracolumbar junction were measured from the lower margin of the 11th thoracic vertebra body to the upper margin of the 2nd lumbar vertebra body on plane radiographs. Adjacent segment disc heights and disc signal changes were determined using simple spinal examinations and by magnetic resonance imaging. Clinical outcome indices were determined using a visual analog scale. RESULTS: The three groups demonstrated statistically significant differences in terms of angle changes by ANOVA (p < 0.05). All angles in group I showed significantly smaller angles changes than in groups II and III by Turkey's multiple comparison analysis. Coronal Cobb's angles of the thoracolumbar spine (TLC) were not significantly different in the three groups. CONCLUSION: Postoperative sagittal balance is expected to change in the adjacent and thoracolumbar areas after thoracic spine fusion. However, its prevalence seems to be higher when the thoracolumbar spine is included in instrumented fusion.

Avaliação clínica da estabilização dinâmica com dispositivo Dynesis em pacientes com dor lombar com seguimento mínimo de seis meses / Evaluation of clinical results of dynamic stabilization with the Dynesis dispositive in patients with lumbar pain with a 6 months minimum follow up

Objetivo: Avaliar o resultado clínico da estabilização dinâmica com o dispositivo Dynesis em pacientes com dor lombar e alteração degenerativa do disco intervertebral. Método: Os autores avaliaram 24 pacientes, com idade média de 43,2anos (26 a 57 anos) com queixa de dor lombar com no mínimo seis meses de tratamento conservador sem melhora e ressonância magnética com alteração degenerativa discal avaliado pela classificação de Pffirmann e preservação da altura do disco de pelo menos 40% na radiografia no plano sagital. Foi realizada a fixação com parafuso dinâmico (Dynesis). A avaliação foi realizada por meio da escala visual análoga para dor. Resultado: A escala visual análoga da dor pré-operatoriamente obteve média de 7,4 pontos e após seis meses caiu para 2,9 pontos de média. Conclusão: Neste estudo concluímos que há uma melhora da dor lombar após estabilização dinâmica com dispositivo Dynesis.