Which is better Stainless Steel or Titanium alloy?

AIM: To investigate immunologic reactions after implantation of stainless steel (SS) alloy and titanium (Ti) alloy in a rat model. Macrophage and cytokine responses have been reported after the in vivo and in vitro application of different biomaterials. MATERIAL AND METHODS: Wistar albino rats after an exploration of the thoracolumbar paravertebral muscle tissue of the subjects, group I underwent a sham surgery, and groups II and III were implanted Ti alloy and SS alloy rods respectively. The CD4, CD8, CD25 (IL-2R) (lymphocyte and CD4 gate), CD4+CD8+ and CD4+CD25+Foxp3+ (Tregs), IL-4, IL-10, IL-6, IL-17A, TGF-ß, TNF-α in the blood were analyzed. RESULTS: CD4, CD25 (IL-2R), CD4+CD8+ and Tregs levels were lower in the Group III compared to the sham and Group IIs. IL-6, IL-17A, TGF-ß and TNF-α levels in the G III showed a significant increase on all days in comparison with the sham and Group II. IL-4 and IL-10 levels, were lower in the Group III than those in the Group II; and a significant decrease was observed in the IL-10 level. While there was a reduction in IL-6 and IL-17A levels in the Group II as opposed to the sham group. CONCLUSION: As opposed to SS alloy, Ti alloy suppresses the development of inflammations by inhibiting proinflammatory response; strengthens the humoral immune system by intensifying the antibody-dependent immune response; triggers the development of immune tolerance by regulating the immune response; and activates the mechanism that prevents immune response-related damage from occurring.

Russell-Silver syndrome associated with low conus medullaris.

Russell-Silver syndrome is a rare heterogeneous disorder mainly characterized by intrauterine and postnatal growth retardation, craniofacial disproportion, clinodactyly, variation in urogenital development, and skeletal asymmetry. It is rare to come across tethered cord-associated Russell-Silver syndrome. We report a rare case of Russell-Silver syndrome associated with low conus medullaris in a 2-year-old patient with demonstrative phenotype. Magnetic resonance imaging indicated a low conus medullaris at the inferior border of the L3 vertebral body. Urodynamic study revealed detrusor-sphincter dyssynergia and detrusor overactivity. A decision to follow-up the patient was made because of the suspicion of tethered cord syndrome. Even though tethered cord syndrome is not a common finding in Russell-Silver syndrome, it is important to consider tethered cord syndrome to avoid scoliosis and other long-term complications.

Unilateral dynamic stabilization for unilateral lumbar spinal pathologies; a new surgical concept.

AIM: Minimally invasive surgical techniques for spine surgery have gained popularity over the last decade. In this study, the authors describe a unilateral dynamic stabilization for unilateral spinal pathologies. MATERIAL AND METHODS: A total of 7 patients with an average age of 46.1 years (range 21-80 years) were included in this study. They are represented various spinal pathologies (degenerative disorders, various tumor pathologies) and having undergone a unilateral facetectomy (or facetectomies) with or without a hemilaminectomy procedure were analyzed in this study. The surgical stabilization was achieved with unilateral dynamic stabilization. RESULTS: The new surgical concept is described here, and the comparative early results of the Oswestry disability index (ODI) and the visual analog scale (VAS) are presented as well. The preoperative average ODI was 73.14 (range 62-94), and the average VAS was 8.14 (range 7-10). Twelve months after the surgery, ODI was 10.6 (range 0-16), and the average VAS was 1 (range 0-2) (p < 0.01). CONCLUSION: Although the limited number of cases analyzed reflects data of only early patient outcome, the procedure is safe, feasible, and cost effective. The unilateral dynamic pedicle screw stabilization without fusion is as a technical option to avoid possible segmental instability after unilateral total facetectomy procedure.

Spontaneous pyogenic spinal epidural abscess.

AIM: Spontaneous pyogenic spinal epidural abscess (SEA) is a rare condition but might be devastating and fatal. Traditional treatment is surgical decompression and antibiotics. A retrospective study was designed to assess the eff ect of clinical findings and treatment methods on the outcome. MATERIAL AND METHODS: 14 patients were reviewed (10 male, 4 female, mean age 59.14). Six dorsal, seven ventral and one dorsal with ventral SEA were observed. SEA found in thoracal (5), lumbar (4), cervical (3) regions. One patient showed both cervical and thoracal and one patient showed cervical, thoracal and lumbar involvement. All patients received minimum 3 weeks of I.V., followed by minimum 3 weeks of oral antibiotics. All patients complained of spinal pain. Ten patients presented with fever. Neurological deficit was observed in 9 cases. RESULTS: A total of 22 interventions was performed. Instrumentation was applied in 5 cases. Full recovery was achieved in 7 patients, significant improvement was observed in 5 patients. The neurological findings did not change in one patient. One mortality and one morbidity were observed. CONCLUSION: Spontaneous SEA is a rare disease but might result in catastrophic neurological deficits and fatal even with prompt treatment. Therefore, one should always keep SEA in mind if a patient presents with fever, vague and spinal pain.

Dynamic lumbar pedicle screw-rod stabilization: two-year follow-up and comparison with fusion.

BACKGROUND: A lumbar pedicular dynamic stabilization system (LPDSS) is an alternative to fusion for treatment of degenerative disc disease (DDD). In this study, clinical and radiological results of one LPDSS (Saphinaz, Medikon AS, Turkey) were compared with results of rigid fixation after two-year follow-up. METHODS: All patients had anteroposterior and lateral standing x-rays of the lumbar spine preoperatively and at 3 months, 12 months and 24 months after surgery. Lordosis of the lumbar spine, segmental lordosis and ratio of the height of the intervertebral disc spaces (IVS) measured preoperatively and at 3 months, 12 months and 24 months after surgery. All patients underwent MRI and/or CT preoperatively, 3months, 12 months and 24 months postoperatively. The ratio of intervertebral disc space to vertebral body height (IVS) and segmental and lumbar lordosis were evaluated preoperatively and postoperatively. Pain scores were evaluated via Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) preoperatively and postoperatively. RESULTS: In both groups, the VAS and ODI scores decreased significantly from preoperatively to postoperatively. There was no difference in the scores between groups except that a lower VAS and ODI scores were observed after 3 months in the LPDSS group. In both groups, the IVS ratio remained unchanged between preoperative and postoperative conditions. The lumbar and segmental lordotic angles decreased insignificantly to preoperative levels in the months following surgery. CONCLUSIONS: Patients with LPDSS had equivalent relief of pain and maintenance of sagittal balance to patients with standard rigid screw-rod fixation. LPDSS appears to be a good alternative to rigid fixation.

Discal cysts of the lumbar spine: report of five cases and review of the literature.

Discal cysts are rare causes of low back pain and radiculopathy. Only few reports in the literature describe these pathologies. In this article, the authors report five cases (3 males and 2 females) of lumbar discal cysts treated surgically by microdiscectomy. These patients were admitted with a history of back pain and/or sciatalgia. Magnetic resonance imaging of the lumbar spine of all patients revealed lumbar discal cysts, causing compression to the spinal dura and roots. All patients were treated by partial hemilaminectomy and microscopic cyst resection. Postoperatively, the complaints showed improvement, and the patients were discharged with no complications. The cases of lumbar discal cysts are described in the literature as individual case reports, therefore; the authors performed a wide systemic review of all these cases published in PubMed and MedLine, including the patients in the present report. The data of all patients were analyzed to obtain statistically based estimated information about the incidence, the epidemiology, the natural history and the optimum management of these lesions.

Dynamic lumbar pedicle screw-rod stabilization: in vitro biomechanical comparison with standard rigid pedicle screw-rod stabilization.

OBJECT: It is unclear how the biomechanics of dynamic posterior lumbar stabilization systems and traditional rigid pedicle screw-rod systems differ. This study examined the biomechanical response of a hinged-dynamic pedicle screw compared with a standard rigid screw used in a 1-level pedicle screw-rod construct. METHODS: Unembalmed human cadaveric L3-S1 segments were tested intact, after L4-5 discectomy, after rigid pedicle screw-rod fixation, and after dynamic pedicle screw-rod fixation. Specimens were loaded using pure moments to induce flexion, extension, lateral bending, and axial rotation while recording motion optoelectronically. Specimens were then loaded in physiological flexion-extension while applying 400 N of compression. Moment and force across instrumentation were recorded from pairs of strain gauges mounted on the interconnecting rods. RESULTS: The hinged-dynamic screws allowed an average of 160% greater range of motion during flexion, extension, lateral bending, and axial rotation than standard rigid screws (p < 0.03) but 30% less motion than normal. When using standard screws, bending moments and axial loads on the rods were greater than the bending moments and axial loads on the rods when using dynamic screws during most loading modes (p < 0.05). The axis of rotation shifted significantly posteriorly more than 10 mm from its normal position with both devices. CONCLUSIONS: In a 1-level pedicle screw-rod construct, hinged-dynamic screws allowed a quantity of motion that was substantially closer to normal motion than that allowed by rigid pedicle screws. Both systems altered kinematics similarly. Less load was borne by the hinged screw construct, indicating that the hinged-dynamic screws allow less stress shielding than standard rigid screws.

A new transodontoid fixation technique for delayed type II odontoid fracture: technical note.

BACKGROUND: A different transodontoid screw fixation technique was studied in delayed type II odontoid fractures. This study presents observations on a different transodontoid fixation technique to remove and decrease the amount of sclerotic layers to accelerate the fusion process after the operation. METHODS: Ten cases of chronic type II odontoid fractures were operated on via transodontoid screw fixation between 2000 and 2007 which were admitted 6 weeks or later after the trauma. Four of these 10 delayed patients were operated on using a new anterior transodontoid screw fixation technique, whereas the other 6 delayed patients were operated on using classical anterior transodontoid screw fixation. RESULTS: Four delayed cases with type II odontoid fracture operated on via this new technique had good results throughout the minimum 38 months' follow-up period. We did not observe nonunion, infection, and/or other complications such as vascular or brain-stem injury. CONCLUSION: Transodontoid screw fixation should be considered as a preferable treatment modality. This surgical intervention may be an alternative to conservative treatment even for cases with delayed type II odontoid fractures.

The results of beta-tricalcium phosphate coated hydroxyapatite (beta-TCP/HA) grafts for interbody fusion after anterior cervical discectomy.

STUDY DESIGN: The efficacy of tricalcium phosphate and hydroxyapatite (beta-TCP/HA) grafts was studied after anterior cervical discectomy (ACD). OBJECTIVE: This study presents our observations about the efficacy of beta-TCP/HA grafts after ACD. SUMMARY OF BACKGROUND DATA: Especially in the last 2 decades, fusion materials such as autograft and allograft, as well as different kind of cages were used to maintain fusion after ACD. METHODS: beta-TCP/HA grafts after ACD were used in 17 patients. The cervical and radicular pain was evaluated via visual analog scale (VAS) score preoperatively, at postoperative third week, and after 20 months (range: 18 to 24 mo) after the operation. The radiologic evaluations were done preoperatively, at postoperative first day and at the latest follow-up. The VAS, intervertebral space ratio, height of intervertebral disc space and neural foramen, and cervical and segmental lordosis angles were recorded preoperatively and during the postoperative follow-up period. The presence of fusion was controlled in computed tomography scans taken at the latest follow-up. RESULTS: Both clinical and radiologic evaluations yielded satisfactory results. VAS scores decreased significantly in all patients. The intervertebral space and neural foramen and intervertebral disc heights increased at postoperative day 1 but were found to be decreased at the latest follow-up (P<0.05). On the contrary the cervical and segmental lordosis angles decreased at postoperative day 1 but were found to be increased at the latest follow-up (P<0.05). There was a solid fusion in 16 out of 17 patients (94.11%). CONCLUSIONS: Although there was a loss of the initially obtained neural foraminal and disc height, the application of beta-TCP/HA graft after ACD resulted in a high rate of fusion and patient satisfaction. Additionally, the cervical and segmental lordosis was preserved. We concluded that it is a good alternative to current methods to maintain cervical alignment and fusion after ACD.

Biomechanical comparison of instrumented and uninstrumented multilevel cervical discectomy versus corpectomy.

STUDY DESIGN: In vitro flexibility test comparing biomechanics of cervical corpectomy versus discectomy with and without instrumentation. OBJECTIVES: To evaluate whether the additional effort required to perform multilevel discectomies instead of corpectomies is worthwhile biomechanically. SUMMARY OF BACKGROUND DATA: Both cervical corpectomy and discectomy have been shown to be effective clinically. No previous biomechanical comparison exists. METHODS: Fourteen human cadaveric cervical spines were studied: 1) intact, 2) after discectomy and wedge grafting at C4-C5, C5-C6, and C6-C7 (Group 1) or corpectomy and strut grafting of C5 and C6 (Group 2), 3) after attaching a locking metal plate from C4-C7, and 4) after adding posterior locking lateral mass screw/rod instrumentation across C4-C7. Non-constraining, nondestructive torques induced flexion, extension, lateral bending, and axial rotation (maximum, 1.5 Nm) while angular motion was measured stereophotogrammetrically. RESULTS: Discectomy and grafting did not alter the range of motion (ROM) significantly from normal during any loading mode (P > 0.11). Corpectomy and grafting allowed a significantly greater range of motion than normal during flexion, lateral bending, and axial rotation (P < 0.05). Addition of an anterior plate reduced ROM to significantly less than normal during all loading modes in both groups (P < 0.005). Addition of posterior instrumentation further reduced ROM significantly in both groups (P < 0.01). There was no significant difference in ROM between corpectomy and discectomy groups in any loading mode whether uninstrumented (P > 0.18), anteriorly plated (P > 0.33), or anteriorly and posteriorly instrumented (P > 0.30). CONCLUSIONS: Less difference in stability was observed than was predicted between specimens receiving multilevel discectomy versus multilevel corpectomy, regardless of whether specimens were left unplated, plated anteriorly, or fixated with combined anterior/posterior instrumentation.

Preserving the ligamentum flavum in lumbar discectomy: a new technique that prevents scar tissue formation in the first 6 months postsurgery.

OBJECTIVE: Postoperative fibrosis is one of the most important causes of failed back surgery syndrome after lumbar disc surgery. Numerous natural and synthetic materials have been investigated as means to prevent or reduce postoperative scarring after these operations. Preservation of the ligamentum flavum for this purpose has not been studied in depth. A prospective, randomized, controlled clinical study was conducted. The aim was to present a new technique for preserving the ligamentum flavum during lumbar discectomy, and to evaluate whether this helps prevent or diminish postoperative fibrosis. METHODS: Twenty patients with unilateral L5-S1 disc herniation were randomly divided into two equal groups. Group A patients underwent classic microlumbar discectomy, and Group B patients underwent the same procedure but with preservation of the ligamentum flavum. Visual analog pain scale (VAPS) scores, Oswestry scale scores, and straight-leg raising angles were recorded preoperatively and at 6 months postoperatively. Differences between the pre-operative and postoperative findings for each group were statistically compared using the Wilcoxon test. Magnetic resonance imaging was also done at 6 months to assess the extent of postoperative fibrosis, and a "scarring grade" was recorded for each patient. The group findings for this were analyzed with Levene's test. RESULTS: Both groups' clinical parameters were significantly improved at 6 months postsurgery. In Group A, the mean pre- and postoperative VAPS scores were 9.2 and 3.2, respectively (P < 0.05); the corresponding mean Oswestry scale scores were 88 and 28.2, respectively (P < 0.05); and the corresponding mean straight-leg raising angles were 290 and 630, respectively (P < 0.05). In Group B, the mean pre- and postoperative VAPS scores were 9.2 and 2.6, respectively (P < 0.05); the corresponding mean Oswestry scores were 85.2 and 22.2, respectively (P < 0.05); and the corresponding mean straight-leg raising scores were 260 and 710, respectively (P < 0.05). The mean scarring grades in Groups A and B were 1.8 and 1.0, respectively (P < 0.05). CONCLUSION: The groups both showed satisfactory clinical outcomes and the improvements were comparable; however, the group with preserved ligamentum flavum showed significantly less local fibrosis at 6 months postoperatively. The authors speculate that this surgical technique provides a physical protective barrier that can reduce or even eliminate fibrosis-related complications after lumbar disc surgery.

Finite element method based stress analysis of zone I and zone II sacral fractures.

BACKGROUND: Sacral bone fractures after direct traumas such as gunshot wounds and blunt sacral traumas are rarely, whereas those occurring after indirect traumas with vertical shear mechanisms ( car accidents or falls) are more frequently seen. METHODS: A cadaver sacrum was modelled 3-dimensionally using finite element software. Left sacroiliac joint was modeled to simulate a 75- kg man falling on one leg from a height of 5 meters. An impact load of 10 kN was transferred to the sacrum via intervertebral disc surface and two facets. Von Mises equivalent stress distribution was estimated. RESULTS: Von Mises stress distribution was calculated for sacral ala (430 MPa), S1 pedicle (225 MPa), and S1 lamina (35 MPa). Stress values were 200 Mpa, 130 Mpa, 105 Mpa, and 55 MPa on ventrolateral, dorsomedial, ventromedial and dorsolateral sides of S1 foramen respectively. Vertical shear injury caused stress distribution to concentrate at sacral ala and S1 pedicle (zone I). Local stress distribution around S1 foramen is concentrated ventrolaterally CONCLUSION: High incidence of zone I sacral fractures and low incidence of neurological deficits could be explained by concentration of stress at sacral ala. Zone II fractures might be due to by transfer of triggered stresses from sacral ala and S1 pedicle to ventrolateral side of S1 foramen.

Biomechanical analysis of rigid stabilization techniques for three-column injury in the lower cervical spine.

STUDY DESIGN: Comparison of nondestructive multidirectional flexibility in groups of specimens receiving two different posterior instrumentation constructs with or without anterior plating. OBJECTIVE: To compare stability after a three-column injury stabilized posteriorly by lateral mass screws-rods at C5-C6 and pedicle screws-rods at C7 ("LLP") or by pedicle screws-rods at C5-C6-C7 ("PPP"), and to compare posterior, anterior, and combined anterior-posterior fixation. SUMMARY OF BACKGROUND DATA: Pedicle screws resist pullout better than lateral mass screws, but little research has compared the stability of pedicle screws to that of lateral mass screws used within constructs. METHODS: Fourteen human cadaveric C4-T1 specimens were tested intact, posteriorly instrumented (7 LLP and 7 PPP), anteriorly instrumented, or with combined (anterior-posterior) instrumentation. Nonconstraining, nondestructive torques induced flexion, extension, lateral bending, and axial rotation while angular motion was recorded optically. RESULTS: Posterior, anterior, and combined instrumentation each significantly improved stability (P < 0.05). Combined fixation provided significantly better stability than either anterior or posterior instrumentation alone. In no loading mode and in no testing condition was any parameter significantly different between LLP and PPP. Posterior instrumentation provided significantly better stability than anterior instrumentation. CONCLUSIONS: Anterior plate and posterior screw-rod fixation alone improve stability in a two-level, three-column cervical injury model. Combined fixation further improves stability. There is little discernible difference in immediate postoperative stability between posterior rod constructs combining lateral mass and pedicle screws and those using only pedicle screws.

Biomechanical comparison of anterolateral plate, lateral plate, and pedicle screws-rods for enhancing anterolateral lumbar interbody cage stabilization.

STUDY DESIGN: A repeated measures in vitro flexibility experiment was performed in calf spines. OBJECTIVES: To determine the biomechanical differences among three techniques for augmenting stability of an anterolateral lumbar threaded interbody cage. BACKGROUND: Stand-alone interbody cages are known to inadequately stabilize the spine. Surgeons often add supplementary instrumentation for a more stable construct. METHODS: Six L2-L5 calf spines (L3-L4 level instrumented) were tested: 1) intact; 2) with a single anterolateral interbody cage; 3) with cage plus anterolateral plating; 4) with cage plus lateral plating; and 5) with cage plus pedicle screw fixation. Specimens were loaded in each anatomic plane quasistatically (maximum 5.0 Nm). Angular motion was measured stereophotogrammetrically. RESULTS: The stand-alone interbody cage allowed significantly less range of motion than normal during all loading modes except axial rotation. Addition of pedicle screws-rods, anterolateral plate, or lateral plate significantly further reduced range of motion in all planes. Pedicle screws slightly outperformed the anterolateral plate during extension and lateral bending and slightly outperformed the lateral plate during flexion, extension, and left axial rotation (range of motion differences <0.65 degrees, P < 0.05). The anterolateral plate outperformed the lateral plate during flexion and extension, whereas the lateral plate outperformed the anterolateral plate during lateral bending (range of motion difference <0.57 degrees, P < 0.05). CONCLUSION: Anterolateral or lateral lumbar plating increases stability significantly compared to stand-alone interbody cage fixation. These findings support anterolateral or lateral plate fixation as a potential clinical alternative to pedicle screws-rods in this role and may obviate the need for combined anterior and posterior approaches when spinal instability exists.

Transvertebral interbody cage and pedicle screw fixation for high-grade spondylolisthesis. Case report.

Surgical stabilization of high-grade lumbosacral spondylolisthesis is clinically challenging, and the success of deformity reduction and fusion varies. The authors describe a patient with Grade III spondylolisthesis at L5-S1. Partial reduction was achieved and fusion involved pedicle screw fixation and a posterior transvertebral interbody cage. This patient had developed progressive spondylolisthesis after decompression and posterolateral fusion for L5-S1 spondylolisthesis failed. Clinical and early radiographic results were excellent. Transsacral cage fixation can be considered a viable option to buttress the region in which high-grade L5-S1 spondylolisthesis has been reduced. The cage provides substrate for interbody arthrodesis and acts as a biomechanical stabilizer that helps prevent pedicle screw failure.

Radiofrequency lesioning using two different time modalities for the treatment of lumbar discogenic pain: a randomized trial.

STUDY DESIGN: A prospective randomized trial. OBJECTIVE: To evaluate the efficacy of percutaneous intradiscal radiofrequency thermocoagulation by modifying the duration of heating, using two different time methods, for relieving pain and improving functional disability. SUMMARY OF BACKGROUND DATA: Lumbar discogenic pain is the major problem in lumbar degenerative disc disease that percutaneous intradiscal radiofrequency thermocoagulation has been suggested for as a nonsurgical invasive treatment technique for lumbar discogenic pain. In a previous controlled study, this method was found to be ineffective with 8 weeks of follow-up. MATERIALS AND METHODS: Sixty patients with chronic low back pain were selected for provocative discography to diagnose the discogenic pain and to locate the discs to be treated. From this group, 39 patients were randomly selected and divided into two groups. In the first group, treatment was performed for 120 seconds, and in the second group for 360 seconds, both at 80C. Patients were assessed with a visual analogue scale for pain relief and functional improvement. Evaluations were performed before, immediately after treatment, at 1 and 2 weeks, and at 1, 3, and 6 months after the procedure. RESULTS: A total of 39 patients with positive provocative discographies were found to eligible for the study. There were no statistical differences in pain relief and functional improvement between two groups (P > 0.05). The immediate, 1-week and 2-week, and 1-month visual analogue scale (VAS) scores were decreased significantly in both groups when comparing them with the pretreatment scores (P < 0.05). However, the final values after 6 months were similar to those measured at the beginning of the study (P > 0.05). CONCLUSION: Percutaneous intradiscal radiofrequency thermocoagulation has been suggested and performed to relieve discogenic pain. In the previous controlled study, no effective pain relief has been obtained. In this study, the authors increased the duration of radiofrequency thermocoagulation to improve the effectiveness of this method. Yet, the authors have not found any significant differences between the application of lesioning at two different times in percutaneous intradiscal radiofrequency thermocoagulation.