Spinal Fixation Surgery Research Articles

Robotic guide system for insertion of screws in spinal fixation surgery

Robotic guide system for insertion of screws in spinal fixation surgery

Successful Spinal Fixation Surgery Following Teriparatide Treatment in an Adolescent Boy with Severe Osteoporosis and Progressive Kyphoscoliosis: A Case Report.

Osteoporosis in individuals with severe kyphoscoliosis can decrease the likelihood of successful surgical fixation and cause substantial morbidity. Loosening of spinal fixation screws and spontaneous vertebral fracture at the fixation site have been reported in patients with severe osteoporosis following surgical fixation1-5. Spinal fixation surgery has gone through numerous changes in the past century, yielding better outcomes for patients. These advances include Harrington rods and hooks in the 1950s, sublaminal wires and anterior approaches in the 1970s, and, popularized by Cotrel et al., transpedicular fixation in the 1980s6-10. Since the 1990s, in order to obtain spinal fusion, there has been a trend to use pedicle screws that are more rigid than previous screws, allowing for greater curvature correction and higher fusion rates11. In addition, new therapies are now being investigated to aid in spinal fusion, including recombinant human bone morphogenetic protein, which stimulates new bone formation at the fusion site and eliminates the need for bone-grafting12,13. However, in patients with osteoporosis, spinal fixation surgery continues to be a challenge. One potential treatment that could be used to improve bone mineral density (BMD) in severe osteoporosis is teriparatide therapy. Teriparatide is the 34-amino acid N-terminal fragment of the parathyroid hormone molecule that can increase BMD, bone strength, and markers of bone turnover14. It is an anabolic drug that has been shown to increase rates of postoperative spinal fusion in rabbits15. Numerous studies show that postmenopausal women with osteoporosis who are treated with teriparatide have increased BMD and a substantial decrease in subsequent vertebral and hip fractures16-19. Teriparatide is particularly appealing for use perioperatively because of the concern for fracture-healing with bisphosphonate treatment20. A recent study showed that …

Remifentanil/propofol total intravenous anesthesia versus remifentanil/isoflurane inhalation anesthesia for controlled hypotension in lumbar spine fixation surgery

Objective The aim of the present study was to design a trial to improve the control of bleeding during spine surgery by controlled hypotension achieved through maintenance of anesthesia using remifentanil with either propofol infusion or isoflurane inhalation. Patients and methods The study included 40 patients assigned for lumbar spine fixation surgery (two levels). Patients were randomly allocated into two equal groups to receive either remifentanil infusion and total intravenous anesthesia with propofol (group I) or remifentanil infusion with isoflurane inhalation anesthesia (group II). The infusion rate of propofol and MAC of isoflurane were adapted to maintain mean arterial pressure in a range of 60-70 mmHg and the heart rate at about 70 beats/min. We compared the amount of intraoperative blood loss, the need for blood transfusion, duration of operation, and surgeon's satisfaction of a bloodless field between both groups. Results There was no statistically significant difference between both groups in operation time ( P = 0.2). The amount of intraoperative blood loss in group I was significantly lower compared with group II ( P = 0.002). The total bleeding score in group I was significantly lower compared with group II ( P = 0.018). Eleven patients required blood transfusion with significantly higher frequency of blood transfusion in group II [nine patients (45%)] than [two patients (10%)] in group I ( P = 0.033). Mean total surgeon satisfaction score in group I was significantly higher compared with group II ( P = 0.014). Conclusion Propofol/remifentanil intravenous anesthesia for spinal fixation surgery is beneficial, allowing properly controlled hypotension, minimized intraoperative bleeding, decreased need for blood transfusion, and improved surgical field visibility, compared with isoflurane/remifentanil anesthesia.

Multistep pedicle screw insertion procedure with patient-specific lamina fit-and-lock templates for the thoracic spine

Pedicle screw fixation is a standard procedure of spinal instrumentation, but accurate screw placement is essential to avoid injury to the adjacent structures, such as the vessels, nerves, and viscera. The authors recently developed an intraoperative screw guiding method in which patient-specific laminar templates were used, and verified the accuracy of the multistep procedure in the thoracic spine. Preoperative bone images of the CT scans were analyzed using 3D/multiplanar imaging software and the trajectories of the screws were planned. Plastic templates with screw guiding structures were created for each lamina by using 3D design and printing technology. Three types of templates were made for precise multistep guidance, and all templates were specially designed to fit and lock on the lamina during the procedure. Plastic vertebra models were also generated and preoperative screw insertion simulation was performed. Surgery was performed using this patient-specific screw guide template system, and the placement of screws was postoperatively evaluated using CT scanning. Ten patients with thoracic or cervicothoracic pathological entities were selected to verify this novel procedure. Fifty-eight pedicle screws were placed using the screw guide template system. Preoperatively, each template was found to fit exactly and to lock on the lamina of the vertebra models, and screw insertion simulation was successfully performed. Intraoperatively the templates also fit and locked on the patient lamina, and screw insertion was completed successfully. Postoperative CT scans confirmed that no screws violated the cortex of the pedicles, and the mean deviation of the screws from the planned trajectories was 0.87 ± 0.34 mm at the coronal midpoint section of the pedicles. The multistep, patient-specific screw guide template system is useful for intraoperative pedicle screw navigation in the thoracic spine. This simple and economical method can improve the accuracy of pedicle screw insertion and reduce the operating time and radiation exposure of spinal fixation surgery.

Timing of tracheostomy after anterior cervical spine fixation

Patients with cervical spinal cord injury frequently undergo early anterior cervical spine fixation (ACSF) and tracheostomy procedures to reduce further deterioration, to reduce risk of pulmonary complications, and to improve patient mobilization. However, tracheostomy is often delayed because of the risk of cross contamination as a result of the proximity to the ACSF incision site. Currently, there is a paucity of studies evaluating this outcome to determine the safety of early tracheostomy after ACSF. In this study, we have evaluated the outcomes and complications associated with early tracheostomy placement. We performed a retrospective review of all patients who underwent tracheostomy placement and ACSF during the same hospitalization between 2005 and 2010. A variety of patient and procedural data were collected, including demographics, timing of ACSF and tracheostomy, length of hospitalization, indication for surgery, American Spinal Injuries Association and Glasgow Coma Scale scores on admission, reason for tracheostomy, method of tracheostomy, and complications. Of the 1,184 patients who underwent an ACSF, 20 (1.7%) required a postfixation tracheostomy. Tracheostomy was performed at mean (SD) of 6.9 (4.2) days after ACSF, ranging from 0 to 17 days. Although nearly half of all patients underwent postfixation tracheostomy within 6 days, no wound or implant infection was seen to occur in any patient. Ten patients (50%) developed ventilator-associated pneumonia, with most cases occurring before tracheostomy (90% vs. 10%, p < 0.0001). Univariate analysis only revealed late tracheostomy to significantly increase the risk of complications (odds ratio, 9.33; 95% confidence interval, 1.19-73.0; p = 0.033). Analysis of all studies in the literature revealed a 1% cross-infection rate, with no cases involving implant contamination. Our findings suggest that early tracheostomy can be performed safely after cervical spine fixation surgery, with no patients developing incisional or implant infections. As the risk of cross contamination is only 1%, early tracheostomy should be strongly considered because of its potential benefits. Therapeutic/care management, level IV.

Delayed Presentation of a Thoracic Aortic Injury With a Vertebral Pedicle Screw

Iatrogenic aortic injuries by pedicle screws are rare but serious complications of spinal fixation surgery. We report the case of a 55-year-old man who underwent surgical correction of traumatic thoracic vertebral fractures at another institution. At 6-month follow-up, computed tomography revealed a nonhealing of the fractures, and a T4 misplaced pedicle screw penetrating the descending thoracic aorta. The patient underwent open aortic repair associated with the anterior vertebral column reconstruction and posterior arthrodesis revision by a vascular and orthopedic surgery team simultaneously.

The correlation between cervical range of motion and misplacement of cervical pedicle screws during cervical posterior spinal fixation surgery using a CT-based navigation system

The aim of this study was to analyze the correlation between cervical range of motion and cervical pedicle screw (CPS) misplacement in cervical posterior spinal fusion surgery using a CT-based navigation system. A total of 46 consecutive patients with cervical posterior spinal fusion surgery using CPSs were evaluated retrospectively. We analyzed the cervical range of motion (ROM) and the misplacement of CPSs that were placed using either separate or single-time multilevel registration with a CT-based navigation system to determine the optimum registration procedure. The screw-inserted vertebra was indicated as Registered vertebra-Pedicle Screw inserted vertebra (Re-PS) = 0, 1, 2, or 3 depending on its distance (level) from the registered vertebra. Grades 0 (no perforation) and 1 (perforations <2 mm) were categorized as "no misplacement." Grades 2 (perforations ≧ 2 mm but < 4 mm) and 3 (perforations ≧ 4 mm) were categorized as "misplacement." We analyzed the correlations between CPS misplacement and Re-PS, and between CPS misplacement and preoperative cervical ROM. Our analysis included 196 screws in patients having a mean age of 53.2 years (range 5-84 years). Level of insertion relative to registration was Re-PS = 0 in 129 screws, Re-PS = 1 in 53, Re-PS = 2 in 10 and Re-PS = 3 in 4. The misplacement rates were 12.2 % (24 screws) overall, 6.2 % in Re-PS = 0, 22.6 % in Re-PS = 1, 20 % in Re-PS = 2, and 50 % in Re-PS = 3. The rate of CPS misplacement increased significantly with a Re-PS = 1 and a Re-PS = 2 and 3 compared to a Re-PS = 0. There was a significant difference in the cervical ROM in each grade and both misplacement groups: 1.8 in Grade 0, 2.3 in Grade 1, 7.8 in Grade 2, 12.9 in Grade 3, 11 in the misplacement group and 1.9 in the no misplacement group. The precision of CPS placement in CT-based navigation surgery was evaluated. The misplacement rate in single-time multilevel registration increased to 23.4 % compared to 6.2 % for separate registration. As the distance increased between the registered level and the level of CPS insertion, the preoperative cervical ROM and the rate of CPS misplacement significantly increased. Thus, the rate of misplacement of CPSs is reduced when performing separate registration. Furthermore, when there is greater preoperative cervical ROM, separate registration would likely improve the safety and accuracy of CPS insertion.

Role of postoperative multislice computed tomography in assessment of pedicle screw placement in spinal surgical fixation

ObjectiveTo evaluate the role of three-dimensional (3D) volume rendering computed tomography (CT), in the postoperative assessment of pedicle screw placement. MethodsNinety-eight patients with previous spinal fixation surgery were included. All inserted screws were evaluated post operatively within the first month using CT. Degree of misplacement and difference between CT images were recorded. ResultsSeventy six, 68 and 39 misplaced screws were detected in 3D reformatted image, coronal reconstruction and axial CT images, respectively. Dorsal spine had the higher rate of violation of 46 (9.95%) with the highest rate at T4 (12.8%) compared with lumbar of 32 (6.9%). Statistically significant differences were found between lateral and medial violation (P value −0.03), between findings of 3D CT reformatted and axial images (P=0.04), and also in detecting end plate perforation and anterior vertebral encroachment in different CT images (P value −0.013). Sensitivity for 3D reformatted image and axial image compared with surgical finding in six revised screws was 100% and 95.8% and specificity was 100% and 88.7%, respectively. Highly momentous agreement is reported with Kappa coefficient=0.95±<0.001. ConclusionWe conclude that postoperative evaluation of pedicle screw using 3D CT reconstruction was a reliable method.

Effects of preoperative β-blocker on blood loss and blood transfusion during spinal surgeries with sodium nitroprusside-controlled hypotension

Background:The present study sought to determine whether premedication with oral β-blocker before hypotensive anesthesia with sodium nitroprusside could improve the quality of surgical field, decrease the blood loss, and decrease the need for homologous blood transfusion and duration of surgery.Methods:Eighty patients scheduled for spinal fixation surgery were included in a prospective, randomized, double-blinded study. Patients were classified into two groups: Group I received oral atenolol 50 mg twice one day before surgery; and Group II received placebo tablets identical in appearance to atenolol tablets for the same period and interval. All patients in both the groups received intraoperative sodium nitroprusside (SNP) as a hypotensive agent. Hemodynamic variables, amount of sodium nitroprusside used, quality of surgical field, and the amount of homologous blood transfusion and blood loss were compared between groups.Results:Heart rate and amount of SNP used were significantly less (P<0.0001) in the atenolol group, but no significant difference was found in intraoperative mean arterial blood pressure (MABP) between the two groups. The time of surgeries was significantly shorter in Group I than in Group II (185±15.21 vs 225±12.61 min), P<0.0001. The quality of surgical field was better in Group I than in Group II in all times of measurements, P<0.0001. The amount of blood loss and the amount of packed red blood cells transfused were significantly less in Group I than in Group II, P<0.0001. No clinically significant complications were observed in either group.Conclusion:Premedication with oral atenolol 50 mg twice/day for one day before hypotensive anesthesia with SNP during spinal surgeries seems to be clinically safe and effective to reduce heart rate, amount of SNP used, amount of blood loss, and amount of blood transfused with better quality of surgical field.

Efficacy of Prophylactic Low Dose of Tranexamic Acid in Spinal Fixation Surgery

Spinal fixation surgery is potentially associated with significant bleeding, often requiring multiple blood transfusions. Concern for the risks of transfusion-acquired infection and immune modulation effects of allogeneic blood has led to the investigation of various hemostatic agents such as tranexamic acid (TXA). The investigators hypothesized that a prophylactic low dose of TXA would reduce blood loss and transfusion requirements during spinal fixation surgery. Of 92 patients, 76 were eligible for participation: 38 patients underwent TXA (10 mg/kg) at the initiation of induction of anesthesia during 10 min followed by intravenous infusion of 1 mg/kg/h (TXA group) and 38 patients received normal saline (control group). General anesthesia was administered and different hemodynamic parameters, complete blood count, abnormal prothrombin time, partial thromboplastin time, fibrinogen level, electrolytes, blood loss, and complications were assessed. Amount of blood transfused to the TXA group (n=10; 675±382 mL) compared with the control group (n=15; 600±220 mL) was not statistically significant (P=0.539). Total intraoperative blood loss was not significantly reduced in the TXA group compared with the control group (1269±690 vs. 1336±550 mL; P=0.659). In the 2 groups, fibrinogen level changed to the same extent and platelet count was reduced. Trend of changes in sodium, potassium, and calcium was the same in either group. No thromboembolic complications were clinically detected in either group. The administration of a prophylactic low dose of TXA did not have a significant effect in the management of intraoperative blood loss and transfusion requirements in patients undergoing spinal fixation surgery.

Editorial Comment from Dr Chang to Decompressive surgery in combination with preoperative transcatheter arterial embolization: Successful improvement of ambulatory function in renal cell carcinoma patients with metastatic extradural spinal cord compression

Suzuki et al.1 performed spinal cord decompression and fixation surgery in combination with preoperative embolization in six non-ambulatory patients due to epidural metastasis from renal cell cancer. After surgery, all patients regained ambulatory function. Suzuki et al.1 presented the necessity of surgical decompression for the preservation of neurological function in cases of metastatic epidural spinal cord compression from renal cell carcinoma (RCC). For the treatment of vertebral metastasis from RCC, radiation therapy is frequently adopted as the first treatment modality. However, in symptomatic metastatic epidural spinal cord compression, radiotherapy has a limited role. In cases in which neurological deficit is progressing despite radiation therapy, emergent surgical decompression should be considered. In most cases in which surgical decompression is performed on time, neurological recovery can be achieved. Ambulatory function is associated with quality of life and prolonged survival. Spinal metastasis of RCC is a highly vascular tumor and intraoperative bleeding was estimated to be in the range 1100–2600 mL even after embolization. Preoperative embolization of spinal tumors is often used to decrease intraoperative blood loss and improve resectability. Its effectiveness in decreasing intraoperative bleeding is definite for spinal metastasis of RCC. Complete embolization of tumors resulted in lower intraoperative blood loss compared with partial embolization and the male gender was associated with increased blood loss.2 The more levels that embolized, the greater the decrease in blood loss.2 The importance of surgical decompression and preoperative embolization in epidural spinal cord compression of RCC should be emphasized to physicians who treat urological cancers. None declared.

3D Interaction Design and Implementation in Virtual Spinal Fixation Surgery System

The 3D interaction design solution and implementation with VTK and QT were proposed in the system of virtual spinal fixation surgery. After discussing the background of 3D interaction technology, the principles of the interaction design about 3D interaction used in the system was given. According to the requirement of the system, the observer pattern and command pattern were adopted. And then 3D interactive design based on 3D Widgets was given in detail, the implementation view was shown. Finally, some implementation interface and five kinds of widgets design were displayed.

Complications of tracheostomy after anterior cervical spine fixation surgery

Purpose Cervical traumatic spinal cord–injured patients often way require both anterior cervical spine stabilization and tracheostomy in the first few days after the injury. The infectious complication of tracheostomy can interfere with the evolution of the fixation surgery. The aim of our study was to evaluate the safety of tracheostomy performed early after anterior cervical spine stabilization. Materials and methods We reviewed the clinical records of 28 patients admitted to our hospital intensive care unit. In all cases, percutaneous tracheostomy was performed using the percutaneous dilation technique. Results The average time interval between the fixation surgery and tracheostomy was 8.25 ± 5.57 days. We had complications in tracheostomy in only 3 cases: minor bleeding occurred in 1 patient and stomal infection, not propagated to the fixation surgery wound, was observed in 2 patients. Two patients died without causal relation to these interventions. Conclusions The early performance of tracheostomy after cervical spinal fixation surgery is safe, still realized early and nearly this, at least if the tracheostomy is performed by percutaneous method.

Haptic Feedback Interaction Design and Implementation in Virtual Spinal Fixation Surgery System

This paper proposed the solution of haptic feedback interaction, which can be used for 3D interaction in Virtual Spinal Fixation Surgery System. We frist introduced the traditional Proxy-based Volume Haptics solution, and then proposed the Haptic feedback primitive based on it. There are four Haptic feedback primitive: point, line, plane and direct force. The haptic feedback system developing model is composed by Haptic Rendering and Graphics Rendering. The paper designed interface and classes based on this model, and then implemented the haptic feedback system at last. With this system, we can feel the load carring condition, speed up the virtual operation and provide data analysis more accurately.

Visualization Design and Implementation in Virtual Spinal Fixation Surgery System

This paper proposed the solution of visualization technology in virtual spinal fixation surgery system, which implemented the 2D image display and 3D bone tissue refactoring. It is designed based on Visualization Toolkit and implemented by the improved RayCasting volume rendering algorithm. First, design the uniform interface for 2D and 3D visualization, and then give 2D slicing visualization pipeline and spine 3D refactoring pipeline. In spine 3D refactoring, the system dynamically chose appropriate rendering algorithm to satisfy the real-time requirement of the system interaction based on GPU or CPU computer hardware environment. Meanwhile, provide visualization windows with visualization pipeline adjustment panel to adjust visualization effect conviniently. By 2D slicing data visualization we can transform CT value into 2D grayscale image and display it. The refactoring algorithm of 3D bone tissue refactors CT visualization data into 3D bone model. By defining the resampling coordinates in 3D refactoring window, the system provides re-slicing of axial section view, sagittal section view and coronary section view.

Proof of concept: In vitro measurement of correlation between radiodensity and ultrasound echo response of ovine vertebral bodies

An acoustic guidance method for pedicle screw placement during spine fixation surgery was recently investigated, with a view toward preventing complications such as injury to the spinal cord, thecal sac, and spinal nerve roots due to screw misplacement. The method relies upon the change in the ultrasound amplitude reflected at different sites—from the outer posterior cortex, through the pedicle, and towards the distal ventral cortex. The amplitude change was empirically observed through in vitro measurement of ultrasound amplitude at the different sites by inserting a 2.5-MHz single element transducer into a vertebral body through insertion pathway created by an advancing screw. This paper provides a theoretical and experimental rationale behind these empirical findings and distance-dependent correlation coefficients between amplitude and bone mineral density within the vertebral body, which approached 97%.

Spinal surgery for acute traumatic spinal cord injury: Implications for nursing

Spinal fixation surgery has become a key option in the management of acute traumatic spinal cord injury. There is, however, considerable debate about the role of spinal surgery in spinal cord injury management and research evidence is conflicting. Nurses have a vital role in the pre- and postoperative care of patients undergoing spinal surgery. Although the principles of pre- and postoperative care are the same as in other surgical procedures, the care of patients with spinal cord injury requires specialist and specific nursing care. There is a need for good quality nursing research that will provide evidence to inform nursing care and enable patients to make informed decisions about their early spinal cord injury management.

Emergent Endovascular Repair as Damage Control Step of Aortic Injury After Posterior Spinal Instrumentation

Emergent Endovascular Repair as Damage Control Step of Aortic Injury After Posterior Spinal Instrumentation

Delayed presentation of aortic injury by pedicle screws: Report of two cases and review of the literature

Perforation of the aorta by pedicle screws is a rare but serious complication of spine fixation surgery. This article reviews the clinical presentation and management of this complication. Presented are two cases of thoracic aorta perforation by a pedicle screw and a review of the appropriate literature performed using a MEDLINE search. Literature review identified eight additional patients. In most cases, aortic perforation was recognized and managed within 18 months of the spine surgery. Clinical presentation included acute bleeding, necessitating urgent exploration in two patients, and pseudoaneurysm formation in five cases, two of which were infected. Depending on the extent of aortic damage and the presence or absence of infection, management ranged from endovascular grafting, to screw burring with closure of the perforation site, to aortic reconstruction with a tube graft and complete orthopedic hardware removal. Outcome was favorable in all patients who were operated on. The small number of reported cases indicates either the rarity of this complication or unawareness of its existence. The true incidence of this complication is probably under-reported. Orthopedic and vascular surgeons should be aware of this potentially fatal problem. Prevention remains the best treatment. Once encountered, a variety of techniques are available to manage this complication with reasonable outcome.

Spinal fixation surgery for acute traumatic spinal cord injury

If the spine is unstable following traumatic spinal cord injury (SCI), surgical fusion and bracing may be necessary to obtain vertical stability and prevent re-injury of the spinal cord from repeated movement of the unstable bony elements. It has been suggested that this spinal fixation surgery may promote early rehabilitation and mobilisation. To answer the question: is there a difference in functional outcome and other commonly measured outcomes between people who have a spinal cord injury and have had spinal fixation surgery and those who have not? The following databases were searched: AMED, CCTR, CINAHL, DARE, EMBASE, HEED, HMIC, MEDLINE, NRR, NHS EED. Searches were updated in May 2003 and MEDLINE was searched again in May 2007. The reference lists of retrieved articles were checked. Randomised controlled trials and controlled trials that compared surgical spinal fixation, with or without decompression, to any other treatment, in patients with a traumatic SCI. Two reviewers independently selected studies. One reviewer assessed the quality of the studies and extracted data. No randomised controlled trials or controlled trials were identified that compared surgical spinal fixation surgery to other treatments in patients with a traumatic SCI. All of the studies identified were retrospective observational studies and of poor quality. The current evidence does not enable conclusions to be drawn about the benefits or harms of spinal fixation surgery in patients with traumatic SCI. Well-designed, prospective experimental studies with appropriately matched controls are needed.