Spinal Fixation Surgery Research Articles

Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study.

To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility. A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility. Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline. Postoperative mobility often temporarily decreases but generally improves after 2years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

Biomechanical Effects of Multi-segment Fixation on Lumbar Spine and Sacroiliac Joints: A Finite Element Analysis.

Spine fixation surgery affects the biomechanical environment in the sacroiliac joint (SIJ), which may lead to the SIJ pain or degeneration after surgery. The purpose of this study is to determine the impact of the number and position of fixed segments on the SIJs and provide references for surgeons to plan fixation levels and enhance surgical outcomes. The intact lumbar-pelvis finite element (FE) models and 11 fixation FE models with different number and position of fixed segments were developed based on CT images. A 400N follower load and 10° range of motion (ROM) of the spine were applied to the superior endplate of L1 to simulate the flexion, extension, bending and torsion motion after surgery. The peak stress on the SIJs, lumbar intervertebral discs, screws and rods were calculated to evaluate the biomechanical effects of fixation procedures. With the lowermost instrumented vertebra (LIV) of L5 or S1, the peak stress on SIJs increased with the number of fixed segments increasing. The flexion motion led to the greater von Mises stress on SIJ compared with other load conditions. Compared with the intact model, peak stress on all fixed intervertebral discs was reduced in the models with less than three fixed segments, and it increased in the models with more than three fixed segments. The stress on the SIJ was extremely high in the models with all segments from L1 to L5 fixed, including L1-L5, L1-S1 and L1-S2 fixation models. The stress on the segment adjacent to the fixed segments was significant higher compared to that in the intact model. The peak stress on rods and screws also increased with the number of fixed segments increasing in the flexion, extension and bending motion, and the bending and flexion motions led to the greater von Mises stress on SIJs. Short-term fixation (≤2 segments) did not increase the stress on the SIJs significantly, while long-term segment fixation (≥4 segments) led to greater stress on the SIJs especially when all the L1-L5 segments were fixed. Unfixed lumbar segments compensated the ROM loss of the fixed segments, and the preservation of lumbar spine mobility would reduce the risks of SIJ degeneration.

Does global spinal alignment affect the use of walking aids after multi-segment spinal fixation for patients with ASD? A multicenter retrospective study.

This study aimed to clarify the relation between global spinal alignment and the necessity of walking aid use in patients with adult spinal deformity (ASD) and to investigate the impact of spinal fixation on mobility status after surgery. In total, 456 older patients with ASD who had multi-segment spinal fixation surgery and were registered in a multi-center database were investigated. Patients under 60years of age and those unable to walk preoperatively were excluded. Patients were classified by their mobility status into the independent, cane, and walker groups. Comparison analysis was conducted using radiographic spinopelvic parameters and the previously reported global spine balance (GSB) classification. In addition, preoperative and 2years postoperative mobility statuses were investigated. Of 261 patients analyzed, 66 used walking aids (canes, 46; walkers, 20). Analysis of preoperative radiographical parameters showed increased pelvic incidence and pelvic incidence-lumbar lordosis mismatch in the walker group and increased sagittal vertebral axis in the cane and walker groups versus the independent group. Analysis of GSB classification showed a higher percentage of walker use in those with severe imbalance (grade 3) in the sagittal classification but not in the coronal classification. While postoperative radiographical improvements were noted, there was no significant difference in the use of walking aids before and 2years after surgery (P = 0.085). A significant correlation was found between "sagittal" spinal imbalance and increased reliance on walking aids, particularly walkers. However, the limitation of improvement in postoperative mobility status suggested that multiple factors influence the mobility ability of elderly patients with ASD.

Bilateral ultrasound-guided erector spinae plane block for postoperative pain relief in major traumatic spine surgery: A randomized controlled trial.

Spine fixation surgery for traumatic vertebral fractures is associated with severe pain and is often difficult to control. Traditionally systemic opioids have been the mainstay of analgesia for these procedures, which can lead to hyperalgesia, nausea, ileus, sedation, cognitive impairment, dependence, etc., limiting usage of opioids. The Erector spinae plane block (ESPB) is a novel ultrasound-guided procedure with easily identifiable sonoanatomy. We hypothesized that a multimodal approach involving ESPB to a conventional analgesic regimen with local infiltration for patients undergoing major traumatic spine surgeries might provide better perioperative analgesia and reduce the need for postoperative opioid requirements. A randomized control prospective trial was conducted on 34 ASA grade I -II patients aged 18 to 65 years who were scheduled to undergo elective posterior spine fixation surgery with ASIA B to E after traumatic spine fracture under general anesthesia. Patients were randomized to Group A which included patients who received general anesthesia with ESPB, and Group B, or the control group, included patients who received general anesthesia with systemic analgesics and postoperative local infiltration without ESPB. Intraoperative total fentanyl consumption, VAS score at 0, 3, 6, 12, 18, and 24 hours, time to activate patient-controlled analgesia (PCA) pump, total morphine consumption, and opioid-related side effects were monitored and compared in both groups. Postoperative PCA morphine consumption was significantly lower in group A patients who received ESPB than those in the control group (17.06 ± 9.59 vs 37.82 ± 9.88 P value = <0.0001). VAS scores at rest and movement at 0, 3, 6, 9, 12, 18, and 24 hours were significantly lower (P value = 0.05) in the ESPB group compared with the control group at all time points. Bilateral ultrasound-guided Erector spinae plane block, when administered in traumatic spine patients undergoing spine fixation surgery, provides better analgesia with statistically decreased VAS scores and less postoperative opioid requirement.

Value of different preoperative bone evaluation methods in predicting intraoperative screw insertion torque: a prospective clinical comparative trial

BACKGROUND CONTEXTEstablishing good screw-bone structural stability is conducive to reducing the risk of postoperative screw loosening. Screw insertion torque is an objective index for evaluating screw-bone structural stability. Therefore, accurate prediction of screw insertion torque can improve the preoperative evaluation of patients, optimize the surgical plan, and improve the surgical effect. At present, the correlation between different bone assessment methods and screw insertion torque is unclear. PURPOSEThe aim of this study was to evaluate the correlation between different bone assessment methods and screw insertion torque and to optimize the predictive performance of screw insertion torque through mathematical modeling combined with different radiology methods. DESIGNProspective cross-sectional study. PATIENT SAMPLESSeventy-seven patients with preoperatively available DXA, CT and MRI data who underwent spinal fixation surgeries between October 2022 and September 2023 and 357 sets of screw data were included in this analysis. OUTCOME MEASURESSpinal, vertebrae-specific and screw trajectory's BMD were measured preoperatively by different imaging modalities. Intraoperative screw insertion torque was measured using an electronic torque wrench. METHODSPearson linear correlation, scatter plots and univariate linear regression were used to evaluate the correlation between different bone evaluation methods and screw insertion torque. Different bone evaluation methods were fitted into the prediction model of screw torque and the related equations were obtained. RESULTSScrew insertion torque had the strongest positive correlation with the volumetric bone mineral density (vBMD) of the screw trajectory (Pedicle screw insertion torque (PSIT): R = 0.618, p<.001; Terminal screw insertion torque (TSIT): R = 0.735, p<.001). A weak negative correlation was found between the screw insertion torque and level specific vertebral bone quality (VBQ) (PSIT: R = -0.178, p=.001; TSIT: R = -0.147, p=.006). We also found that the PSIT was strongly correlated with the TSIT (R = 0.812, p<.001). CONCLUSIONSCompared to other bone quality assessment methods, screw trajectory vBMD may be better predict the magnitude of screw insertion torque. In addition, we further optimized preoperative assessments by constructing a mathematical model to better predict screw insertion torque. In conclusion, clinicians should select appropriate preoperative bone quality assessment methods, identify potential low-torque patients, optimize surgical plans, and ultimately improve screw insertion accuracy and reduce postoperative screw loosening rate.

A Randomized Controlled Study of Epidural Morphine Sulfate-soaked Gelfoam and Morphine Sulfate Instillation in the Management of Postoperative Pain following Lumbar Spinal Fixation Surgery

Abstract Background: Lumbar spinal fixation surgeries play a pivotal role in addressing pain which can be nociceptive, neuropathic, mixed, and nociplastic; however, these surgeries can also cause significant postoperative pain and discomfort, leading to prolonged hospital stays and delayed return to normal activity. Aims and Objectives: The aim of the study was to provide effective postoperative analgesia and to compare the analgesic efficacy by application of Gelfoam-soaked morphine sulfate placed in the epidural space and direct instillation of morphine sulfate in the epidural space in patients undergoing lumbar spinal fixation surgery under general anesthesia. Materials and Methods: A total of 60 patients planned for Lumbar spinal fixation surgeries were selected and sorted into two groups of 30 each after a computer-based randomization. In Group G, a 5 cm × 1 cm piece of absorbable gelatin sponge soaked in 5 mg of morphine sulfate diluted in 0.9% normal saline up to 5 mL was placed in the epidural space. In Group I, 5 mg of morphine sulfate diluted in 0.9% normal saline 5 mL was instilled over the intact epidural space. Pulse rate, mean arterial pressure (MAP), respiratory rate (RR), and peripheral oxygen saturation (SpO2) were observed hourly for the first 6 h, then at 2 hourly intervals till 12 h, and at 4 hourly intervals till 48 h. Postoperatively, pain intensity is assessed by the Visual Analog Scale (VAS) for 24 h, and the time of the first analgesic dose is noted. VAS ranges from 0 (no pain) to 10 (severe pain). Preoperative instructions were given to the patients about the use of VAS. Results: In this study, Group G demonstrated lower postoperative VAS scores and delayed need for rescue analgesia compared to Group I (P &lt; 0.05, P &lt; 0.0001, respectively). Group I had a higher total analgesic requirement (P &lt; 0.0001) and consistently higher heart rates (P &lt; 0.0001) compared to Group G. MAPs were lower in Group G compared to Group I (P &lt; 0.0001). RRs, SpO2, sedation scores, and incidence of nausea and pruritus were similar between the two groups (P &gt; 0.05). Conclusion: Epidural administration of morphine using Gelfoam as a vehicle for sustained release of morphine is a safe and effective method of postoperative analgesia in lumbar spinal fixation surgeries and results in better hemodynamics, prolonged duration of analgesia, and reduced requirement of rescue analgesics, compared to epidural instillation of morphine.

Bone union-promoting effect of romosozumab in an ovariectomized rat posterolateral lumbar fusion model.

Spinal fixation surgery has been increasingly performed in patients with osteoporosis. Romosozumab, a drug that was introduced in Japan recently, is known to possibly promote bone healing. However, few studies have reported the therapeutic effects of romosozumab in clinical practice in Japan. Therefore, here, we investigated the effects of romosozumab dosage on bone fusion promotion using an ovariectomized rat spinal fusion model. Eight-week-old female Sprague-Dawley rats were matched by body weight and divided into three groups: 1.0 romosozumab (R) group (Evenity®, 25 mg/kg), 1/10R group (Evenity®, 2.5 mg/kg), and control (C) group (saline). Subcutaneous injections were administered twice a week for 8 weeks postoperatively. Computed tomography scans were performed every 2 weeks from the time of surgery till 8 weeks postoperatively. The mean fusion rates in terms of volume were significantly higher in the R groups [1/10R, 1.0R] than in the C group from 4 weeks postoperatively. The rate of increase was significantly higher in the 1.0R group from 4 weeks postoperatively and in the 1/10R group from 6 weeks postoperatively, than in the C group. The proportion of trabecular bone area was approximately 1.5 times higher in the R groups than in the C group. No significant differences were observed between the R groups. Our results suggest that romosozumab stimulates bone growth at the graft site, and similar effects were achieved at 1/10 of the standard dosage.

The positional consistency between guidewire and cannulated or solid screw in robot-assisted spinal internal fixation surgery

BackgroundThis study aimed to investigate the positional consistency between the guidewire and the screw in spinal internal fixation surgery.MethodsThis study involved 64 patients who underwent robot-assisted thoracic or lumbar pedicle screw fixation surgery. Guidewires were inserted with the assistance of the Tirobot. Either cannulated screws or solid screws were inserted. Guidewire and screw accuracy was measured using CT images based on the Gertzbein and Robbins scale. The positional consistency between guidewire and screw was evaluated based on the fused CT images, which could graphically and quantitatively demonstrate the consistency. The consistency was evaluated based on a grading system that considered the maximum distance and angulation between the centerline of the guidewire and the screw in the region of the pedicle.ResultsA total of 322 screws were placed including 206 cannulated ones and 116 solid ones. Based on the Gertzbein and Robbins scale, 97.5% of the guidewires were grade A, and 94.1% of the screws were grade A. Based on our guidewire-screw consistency scale, 85% in cannulated group, and 69.8% in solid group, were grade A. Both solid and cannulated screws may alter trajectory compared to the guidewires. The positional accuracy and guidewire-screw consistency in the solid screw group is significantly worse than that in the cannulated screw group. The cortical bone of the pedicle has a positive guide effect on either solid or cannulated screws.ConclusionThe pedicle screws may alter trajectory despite the guidance of the guidewires. Solid screws show worse positional accuracy and guidewire-screw consistency compared with cannulated screws.Trial registration The study was retrospectively registered and approved by our center’s institutional review board.

First-in-Human Results of a Non-Opioid Implantable Anesthetic in Spine Fixation Surgery

First-in-Human Results of a Non-Opioid Implantable Anesthetic in Spine Fixation Surgery

Effect of Traditional Chinese Medicine hot compress and acupoint application on prevention of abdominal distension and constipation after multiple-level spinal fixation surgery

Effect of Traditional Chinese Medicine hot compress and acupoint application on prevention of abdominal distension and constipation after multiple-level spinal fixation surgery

Plastic surgeon closure is comparable to orthopedic closure when a perioperative optimization protocol is instituted for pediatric patients with neuromuscular scoliosis

Background ContextSince 2015, plastic multilayer closure (PMC) has been gaining attraction due to improved wound healing outcomes for medically complex patients. Plastic multilayer closure has been readily used for complex spine surgery closures in patients susceptible to wound healing issues (ie, dehiscence, surgical site infection [SSI]). However, PMC requires extensive soft tissue manipulation compared with standard orthopedic spine surgeon closure (SOC) and can result in extended operative times, increased transfusion rates, and more frequent returns to the operating room. PurposeFrom 2016 to 2019, our institution implemented a perioperative protocol designed to decrease postoperative complication rates in NMS patients. A retrospective cohort study was performed to determine if PMC imparted advantages over SOC above and beyond that from the perioperative protocol. Study Design/SettingRetrospective study at a single academic institution. Patient SampleEighty-one pediatric patients with neuromuscular scoliosis undergoing spinal fixation surgery. Outcome MeasuresPostoperative wound complications such as surgical site infection, hematoma, and superficial/deep dehiscence were the main outcome measures. Respiratory and neuromuscular complications along with duration of surgery were also recorded. MethodsA retrospective review was conducted of NMS patients undergoing spinal fixation at a single academic pediatric hospital over 4 years. Cases were labeled as SOC (n=41) or PMC (n=40) based on the closure technique applied. Reported 90-day complications were evaluated as the primary outcome. ResultsOf the 81 reviewed patients, 45 reported complications, roughly equal between the study groups. While we found no statistically significant differences in rates of postoperative complications or SSIs, SOC cases were 30 minutes shorter on average with fewer returns to the operating room for additional surgery. ConclusionsWith the implementation of our perioperative protocol for NMS patients, PMC did not result in fewer complications than SOC but the surgeries did take longer.

Efficacy of Antibiotic Bone Cement in the Treatment of Burkholderia cepacia Infection After Spinal Internal Fixation Surgery: Case Report and Literature Review

In recent years, the number of spinal internal fixation operations has increased significantly, correlating with an elevated risk of postoperative surgical site infection and a rising incidence rate. While the conventional treatment approach involves surgical debridement combined with antibiotic administration, there is a notable gap in reported strategies for Burkholderia cepacia infection and patients exhibiting multidrug resistance. Surgical site infection occurred in a patient following internal fixation surgery for thoracic vertebral fractures. Despite the application of systemic antibiotics and regular dressing changes, no improvement was observed. Bacterial culture and drug sensitivity experiments revealed a multidrug-resistant Burkholderia cepacia infection. Two comprehensive debridement procedures were performed along with continuous post-operative irrigation combined with antibiotic administration; however, no significant improvement was observed. The patient's infection was significantly controlled following treatment with vancomycin loaded bone cement. Following spinal internal fixation surgery, the management of a B.cepacian infection with multidrug resistance presented a significant challenge, despite the application of debridement procedures and systemic antibiotics. In this case, after 20days of treatment with vancomycin-loaded bone cement, the patient's C-reactive protein level decreased to 54mg/L, was normalized by February, and normal levels were maintained in the surgical area 1month and 6months after bone cement removal. The use of vancomycin-loaded bone cement proves effective in treating postoperative B.cepacian infection in a multidrug-resistant case following spinal internal fixation surgery.

Evaluation of the Use of Monopolar Low-Temperature Plasma Electrode in Lumbar Spinal Canal Expansion, Decompression, Bone Grafting, and Fusion Internal Fixation Surgery

Objective: This study aims to explore the therapeutic effects of using a monopolar low-temperature plasma electrode and a high-frequency electrotome during lumbar spinal canal expansion, decompression, bone grafting, and fusion internal fixation surgery. The study also investigates the impact of these techniques on inflammatory indicators and quality of life in patients. Methods: A total of 100 patients with lumbar spondylolisthesis treated between June (January) 2022 and July (March) 2023 were selected for this study. They were randomly divided into a control group and an observation group, with 50 cases in each group. Both groups underwent lumbar spinal canal expansion, decompression, bone grafting, and fusion internal fixation surgery. The control group used a high-frequency electrotome during surgery, while the observation group used a monopolar low-temperature plasma electrode. Surgical indicators (operation time, intraoperative blood loss), inflammatory indicators, pain levels, and quality of life were compared between the two groups. Results: The operation time in the observation group was shorter than that in the control group (P&lt;0.05). Postoperative levels of TNF-α and CRP were lower in the observation group than in the control group (P&lt;0.05). The observation group had lower VAS scores and higher SF-36 scores compared to the control group (P&lt;0.05). Conclusion: The use of a monopolar low-temperature plasma electrode in lumbar spinal canal expansion, decompression, bone grafting, and fusion internal fixation surgery yields positive therapeutic outcomes. It effectively reduces operation time, alleviates patient's inflammatory responses and pain levels, aids in postoperative recovery, and enhances quality of life. These results suggest the potential for wider adoption.

Multimodal analgesia regime for open spine fixation surgery: A case series

Postoperative pain is a common and significant problem that affects millions of patients worldwide. Inadequate pain control can lead to a range of negative outcomes, including prolonged hospital stays, delayed recovery, increased healthcare costs, and decreased patient satisfaction. Therefore, effective management of postoperative pain is essential for improving patient outcomes and reducing healthcare utilization. While progress has been made in improving postoperative pain management, there are still significant gaps in our understanding of the mechanisms underlying postoperative pain and the most effective interventions for its management. Further research is needed to optimize pain management strategies and reduce the burden of postoperative pain on patients and healthcare systems.Multimodal analgesia is an approach to pain management that uses a combination of medications and other interventions to effectively manage pain while minimizing side effects. The goal is to target pain at different points in the pain pathway, using different mechanisms of action, to achieve better pain control than could be achieved with a single medication alone. By using multiple medications that work through different mechanisms, a lower dose of each medication can be used, reducing the risk of side effects. The approach is often tailored to the individual patient, taking into account their medical history, the type of surgery or injury, and their level of pain. Overall, multimodal analgesia aims to improve pain control and patient outcomes while reducing the risk of adverse effects.

Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

The Preoperative Use of Gabapentinoids for the Treatment of Acute Postoperative Pain Following Lumbar Spine Fixation Surgery

A prospective, randomized, controlled, and double-blind trial. Postoperative pain following posterior fixation is caused not only by tissue injury during surgery and is related to inflammatory, neuropathic, and visceral pain. This study aims toanswer the question "Is there a role of gabapentinoids in reducing postoperative pain?" In addition, it demonstrates which gabapentinoidsmaybe used for how long and at what dose. The study was planned as a prospective, randomized, double-blind study. Lumbar posterior fixationwasincluded and patientswere divided into 9 groups. Gabapentinoids and a placebo were administered. Postoperative pain at hours1,6,12, and 24 was evaluated by VAS RESULTS: This study consisted of 252 patients (141 women, 111 men). The median age was 51.62 years. A statistically significant difference was found when VAS-1, VAS-6, VAS-12, and VAS-24 scores were compared between all groups (p˂0.001). Single and low doses of gabapentinoids were found to be ineffective (p˃0.05). Long-term and high-dosegabapentinoids had complications (p˂0.001). Single and high doses of gabapentinoids were effective and safe (p˂0.001). Postoperativeuse of gabapentin for controlling early and late-stage pain is safe and effective. singlesingle and high-dose gabapentin was the first choice. A single and high dose of pregabalin is the second choice.

Effectiveness of Stellate Ganglion Block in Pain Management of Complex Regional Pain Syndrome (CRPS) Type II of Upper Extremity

Complex Regional Pain Syndrome (CRPS) is a Neuropathic Pain (Neu-P) Syndrome that lacks clear comprehension and could potentially have diverse causal origins. The occurrence of this syndrome following trauma is frequent, as reported in the literature. We report a patient with a history of spinal cord injury at C6/7 &amp; C7/T1 levels in RTA, who underwent cervical spine fixation surgery, and developed hyperalgesia, allodynia, edema, and color changes in the upper limb 3-4 weeks after surgery. A multimodal therapeutic technique was implemented in the present study, incorporating a stellate ganglion block intervention, which resulted in notable benefits. These benefits included a reduction in pain scores and an improvement in mobility of the affected limb.

To Brace or not to Brace after Lumbar Spine Fixation Surgery? A Randomized Controlled Trial and Literature Review.

To Brace or not to Brace after Lumbar Spine Fixation Surgery? A Randomized Controlled Trial and Literature Review.

Evaluating the accuracy of screw placement using intraoperative computed tomography with navigation in dorsal and lumbo-sacral spine fixation surgery

Evaluating the accuracy of screw placement using intraoperative computed tomography with navigation in dorsal and lumbo-sacral spine fixation surgery

Perpendicular probing and screwing technique: A simple method for accurate pedicle screw placement based on the human internal reference frame for angle estimation.

The pedicle screw (PS) is widely used for spinal fixation surgery. However, PS malpositioning can cause critical complications; thus, the accuracy of ascertaining PS trajectory is paramount. This study aimed to demonstrate the accuracy and safety of a simple and cost-effective PS placement technique using a human internal reference frame for angle estimation. Ex vivo lumbar porcine spine samples were fixed to a wooden board with rostrocaudal and mediolateral rotational angles adjusted by two angle vises. PS entry points (EPs) were identified using clear anatomical vertebral landmarks. PS placement was performed on one side using the perpendicular probing and screwing technique (PPST), wherein the attitude angle of the sample was adjusted such that the longitudinal axis of the target pedicle was perpendicular to the ground. The pedicle probe and PS driver were manually maintained perpendicular to the ground during probing and PS placement. PS placement on the contralateral side was performed freehand as a control. Offsets between the preoperatively planned and implanted PS rotational angles measured using computed tomography for PPST and freehand method were analyzed. Pedicle wall penetration was also evaluated. The mean ± standard error of the medial rotational offsets was 5.83° ± 0.57° in the freehand group versus 2.89° ± 0.31° in the PPST group (p <0.001), and the rostrocaudal rotational offsets were 4.81° ± 0.65° in the freehand group versus 2.92° ± 0.45° in the PPST group (p = 0.01). The mean pedicle wall penetration distance was significantly reduced by PPST (0.28 ± 0.12 mm vs 0.80 ± 0.17 mm in the freehand group, p = 0.0071). Thus, PPST improved PS positioning accuracy, resulting in reduced pedicle wall penetration and increased PS placement safety. This simple technique is also potentially cost-effective for institutions without computer-assisted surgical systems.