Pedicle Fracture Research Articles

Discussion of the Current Treatment Methods for Degenerative Lumbar Spondylolisthesis

Degenerative spondylolisthesis (DS) is caused by degeneration that causes the lumbar vertebral body of the diseased segment to be displaced relative to the lower vertebral body, which is usually forward, and is not accompanied by pedicle fracture or defect, also known as "pseudospondylolisthesis". DS is more common in the L4/L5 segment, followed by the L3/L4 and L5/S1 segments, and is mostly mild slippage of the first and second degrees [2-4]. At present, the pathogenesis of DS is not fully understood, and it may be related to age-related degeneration of supporting structures, such as intervertebral discs, facet joints, bones, ligaments, facet capsule, and paravertebral muscles. In addition, the decrease in estrogen in women is also associated with the development of DS [1]. Clinically, DS is characterized by recurrent symptoms such as low back and leg pain, numbness of the lower limbs, intermittent claudication, and in severe cases, colorectal symptoms may occur [4].

Prevalence, Implications, and Risk Factors of Traumatic Dural Tears in Thoracic and Lumbar Fractures: A Retrospective Study.

Introduction Spine fracture in association with traumatic dural tear is a serious injury. A traumatic dural tear is difficult to determine based on initial clinical presentation and radiological imaging even with magnetic resonance imaging (MRI). However, during decompression surgery, cerebrospinal fluid leaks surrounding the injured segments are usually confirmed by directly visualizing them. For preoperative planning and intraoperatively limiting further damage to the dural and neurological structures, early detection of traumatic dural tears before surgery is important. This study aims to determine the prevalence, implication, risk factors, and complications of traumatic dural tears in patients who have undergone surgical treatment for thoracic and lumbar fractures. We believe our retrospective study would identify more accurate risk factors for traumatic dural tears and aid us with preoperative planning and operative precaution. Methods This study retrospectively included all patients who had thoracic and lumbar fractures and had posterior instrumentation and decompression surgery at three hospitals in the Northern region of Malaysia from January 2018 to December 2020. Fractures associated with pathological spine including metastatic, severe osteoporosis, ankylosing spondylitis, metabolic bone disease, those with missing data, and iatrogenic dural tears were excluded from this study. Preoperative and postoperative neurological assessments based on theAmerican Spinal Injury Association (ASIA) impairment scale, blood loss volume, duration of the surgery, and post-surgery complications were gathered from medical records. Interpedicular distance, ratio of central canal diameter, laminar fracture gap, and pedicle fractures were identified and measured. The obtained data was analyzed using Pearson's chi-square and Fisher's exact test for categorical variables, and independent t-test/Mann-Whitney test for numerical variables. Result This study comprised a total of 93 patients who had fractures in their thoracic and lumbar regions. The mean age of the patients was 38 years. The number of patients with traumatic dural tears was 20 (21.5%). There was an association between the presence of dural tears and preoperative neurological deficits (P<0.001). Wider mean interpedicular distance (P=0.004), increased central canal diameter ratio (P<0.001), and displaced laminar fracture (P<0.001) were significantly higher in patients with traumatic dural tears. Multiple logistic regression analysis showed both incomplete (P=0.002) and complete (P=0.037) preoperative neurological deficit, increase of central diameter ratio of encroachment (P=0.011), and presence of >2mm laminar fracture gap (P=0.015) had a significant association with a traumatic dural tear. This study found that patients with traumatic dural tears had longer surgical times and statistically larger mean blood loss volumes when compared to patients without dural tears (P<0.001). There is no significant association between the complications following the surgery and the presence of a dural tear (P>0.05). Conclusion This study shows that the presence of preoperative neurological deficits, wider interpedicular distance, severe canal encroachment, and wide separation of laminar fracture may indicate the likelihood of traumatic dural tear in spine fracture. These factors will enable surgeons to enhance their operational planning and make early preparations for the management of dural tears.

Early Experience With Novel Molded Allograft Anchors for the Management of Screw Loosening in Elderly Patients With Reduced Bone Density in Primary and Revision Lumbar Surgery.

Various strategies have been used to reduce pedicle screw loosening following lumbar instrumented fusion, but all strategies have limitations. In this prospective multicenter cohort study, outcomes of elderly patients with reduced bone density who underwent primary or revision fusion surgery using a novel technique of pedicle screw augmentation with demineralized bone fiber (DBF) anchors were evaluated. This study included elderly patients (aged >65 years) with dual-energy x-ray absorptiometry-confirmed reduced bone density who required lumbar pedicle screw fixation and were treated with supplemental DBF allograft anchors during primary or revision surgery. The need for DBF anchors was determined by evaluating preoperative computed tomography (CT) scans (for revision surgery) and by the surgeons' tactile feedback intraoperatively during pedicle screw insertion and removal. After determining the pedicle screw void diameter with a sizing instrument, DBF anchors and pedicle screws of the same diameter were placed into the void. CT scans were obtained on postoperative day 2 to assess pedicle breach, pedicle fracture, or anchor material extrusion and at 6 and 12 months postoperatively to assess screw loosening. Thereafter, to minimize radiation exposure, CT scans were only performed for recurrence of pain. Twenty-three patients (79% women; mean age, 74 years) received 50 lumbosacral pedicle screws augmented with DBF anchors. Most surgeries (n = 18, 78%) were revisions, and most anchors were inserted into revision pedicle screw trajectories (n = 33, 66%). Day-2 CT scans revealed no pedicle breach/fracture or extrusion of anchor material. During a mean follow-up of 15 months (12-20 months), no screw loosening was detected, and no patient required pedicle screw revision surgery. There were no adverse events attributable to DBF allografts. DBF allograft anchors appear to be safe and effective for augmenting pedicle screws during revision surgeries in female elderly patients with reduced bone density. Clinically, DBF reduced the rate of pedicle screw loosening in patients with reduced bone density. A significant reduction in screw loosening can decrease the need for revision surgeries, which are costly and carry additional risks. Enhanced bone integration from the DBF may promote better healing and long-term stability.

Risk factors for bone cement dislodgement following balloon kyphoplasty for osteoporotic vertebral compression fracture

ObjectiveThe study aimed to determine the incidence and risk factors associated with bone cement dislodgement in patients with osteoporotic vertebral compression fracture following balloon kyphoplasty treatment. MethodsA retrospective study was conducted on 203 patients who underwent kyphoplasty in 255 vertebral bodies between January 2017 and December 2021. The patients were categorized into two groups: the bone cement dislodgment group (n = 16) and the non-bone cement dislodgement group (n = 239). Various patient characteristics and radiologic parameters were evaluated. Statistical analysis involved the assessment of the background homogeneity of the group by using independent sample t tests, chi-square tests, and Fisher’s exact. Univariate and multivariate logistic regression analyses were performed to explore the impact of background variables on cement dislodgement. ResultsThe results revealed that split-type fracture (χ2 = 31.706, p < 0.001), DISH (χ2 = 18.827, p = 0.011), pedicle fracture (χ2 = 22.246, p < 0.001), endplate deficit (χ2 = 14.023, p < 0.001), posterior wall injury (χ2 = 29.124, p < 0.001), and intervertebral vacuum cleft (χ2 = 21.469, p < 0.001) were the factors that significantly differed between the two groups. The multivariate logistic regression analysis revealed posterior wall injury (OR = 12.983, p = 0.025) and intervertebral vacuum cleft (OR = 5.062, p = 0.024) to be independent risk factors. ConclusionThe incidence of bone cement dislodgement in our study was 6.3%. This study underscores the importance of using preoperative radiologic parameters to predict the risk of bone cement dislodgement following balloon kyphoplasty.

Transforaminal endoscopic lumbar discectomy with two-segment foraminoplasty for the treatment of very highly migrated lumbar disc herniation: a retrospective analysis.

The surgical resection of very highly migrated lumbar disc herniation (VHM-LDH) is technically challenging owing to the absence of technical guidelines. Hence, in the present study, we introduced the transforaminal endoscopic lumbar discectomy (TELD) with two-segment foraminoplasty to manage VHM-LDH and evaluated its radiographic and midterm clinical outcomes. The present study is a retrospective analysis of 33 consecutive patients with VHM-LDH who underwent TELD with two-segment foraminoplasty. The foraminoplasty was performed on two adjacent vertebrae on the basis of the migration direction of disc fragments to fully expose the disc fragments and completely decompress the impinged nerve root. The operation duration, blood loss, intra- and postoperative complications, and recurrences were recorded. Additionally, imageological observations were evaluated immediately after the procedure via magnetic resonance image and computerized tomography. Clinical outcomes were evaluated by calculating the visual analog scale (VAS) score and Oswestry Disability Index (ODI). The MacNab criterion was reviewed to assess the patients' opinions on treatment satisfaction. The resection rate of bony structures were quantitatively evaluated on postoperative image. The segmental stability was radiologically evaluated at least a year after the surgery. Additionally, surgery-related and postoperative complications were evaluated. The average age of the patients was 56.87 ± 7.77 years, with a mean follow-up of 20.95 ± 2.09 months. The pain was relieved in all patients immediately after the surgery. The VAS score and ODI decreased significantly at each postoperative follow-up compared with those observed before the surgery (P < 0.05). The mean operation duration, blood loss, and hospital stay were 56.17 ± 16.21min, 10.57 ± 6.92 mL, and 3.12 ± 1.23 days, respectively. No residual disc fragments, iatrogenic pedicle fractures, and segmental instability were observed in the postoperative images. For both up- and down- migrated herniation in the upper lumbar region, the upper limit value of resection percentage for the cranial SAP, caudal SAP, and pedicle was 33%, 30%, and 34%, respectively; while those in the lower lumbar region was 42%, 36%, and 46%, respectively. At the last follow-up, the satisfaction rate of the patients regarding the surgery was 97%. Surgery-related complications including dural tear, nerve root injury, epidural hematoma, iatrogenic pedicle fractures, and segmental instability were not observed. One patient (3%) suffered from the recurrence of LDH 10 months after the initial surgery and underwent revision surgery. The TELD with two-segment foraminoplasty is safe and effective for VHM-LDH management. Proper patient selection and efficient endoscopic skills are required for applying this technique to obtain satisfactory outcomes.

Risk Factors for Residual Back Pain After Balloon Kyphoplasty for Osteoporotic Vertebral Fracture.

Balloon kyphoplasty (BKP) is a method for the management of osteoporotic vertebral body fracture (OVF). However, improvement in back pain (BP) is poor in some patients, also previous reports have not elucidated the exact incidence and risk factors for residual BP after BKP. We clarified the characteristics of residual BP after BKP in patients with OVF. In this study, we hypothesize that some risk factors may exist for residual BP 2years after the treatment of OVF with BKP. A multicenter cohort study was performed where patients who received BKP within 2months of OVF injury were followed-up for 2years. BP at 6months after surgery and final observation was evaluated by Visual Analog Scale (VAS) score. Patients with a score of 40mm or more were allocated to the residual BP group, and comparisons between the residual back pain group and the improved group were made for bone density, kyphosis, mobility of the fractured vertebral body, total spinal column alignment, and fracture type (fracture of the posterior element, pedicle fracture, presence or absence of posterior wall damage, etc.). Also, Short Form 36 (SF-36) for physical component summary (PCS) and mental component summary (MCS) at the final follow-up was evaluated in each radiological finding. Of 116 cases, 79 (68%) were followed-up for 2years. Two years after the BKP, 26 patients (33%) experienced residual BP. Neither age nor sex differed between the groups. In addition, there was no difference in bone mineral density, BKP intervention period (period from onset to BKP), and osteoporosis drug use. However, the preoperative height ratio of the vertebral body was significantly worse in the residual BP group (39.8% vs. 52.1%; p = 0.007). Two years after the operation, the vertebral body wedge angle was significantly greater in the residual BP group (15.7° vs. 11.9°; p = 0.042). In the multiple logistic regression model with a preoperative vertebral body height ratio of 50% or less [calculated by receiver operating characteristic (ROC) curve], the adjusted odds ratio for residual BP was 6.58 (95% confidence interval 1.64-26.30; p = 0.007); similarly, patients with vertebral body height ratio less than 50% had a lower score of SF-36 PCS 24.6 vs. 32.2 p = 0.08. The incidence of residual BP 2years after BKP was 33% in the current study. The risk factor for residual BP after BKP was a preoperative vertebral body height ratio of 50% or less, which should be attentively assessed for the selection of a proper treatment scheme and to provide adequate stabilization. III.

Hollow Screw Placement Combined with Percutaneous Vertebroplasty Serves as a Valuable Three-Column Intensive Treatment for Patients with Kummell's Disease and Pedicle Rupture.

To introduce the surgical methods and clinical results of percutaneous vertebroplasty (PVP) combined with hollow screw placement as a treatment for patients with Kummell's disease and pedicle rupture. From January 2020 to January 2023, a total of 10 patients with Kummell's disease and pedicle rupture confirmed via imaging underwent three-column intensive therapy using hollow screws combined with PVP. There were two males and eight females with an average age 75.7±6.11 years old. The time of operation, bone cement injection amount, bone cement leakage during operation were recorded. X-ray and CT were reexamined after operation. The improvement in quality of life was assessed using the Oswestry Disability Index (ODI), and the improvement in low back pain was assessed using the visual analogue scale (VAS). Hollow screw placement combined with PVP was successfully performed in all patients. The average operation time was 39.2±5.1 min, and the average volume of bone cement injected was 5.85±0.83mL. No leakage of bone cement into spinal canal occurred.The mean preoperative ODI score was 75.70±4.39, but this decreased significantly postoperatively(P<0.05), being 37.70±6.95 at 1 day and 26.40±4.90, 23.70±4.87, 21.70±5.46, and 20.50±4.21 at 1, 3, 6, and 12 months after the operation, respectively. The mean VAS pain score before the operation was 8.35±0.63, but the symptoms of back pain were significantly relieved after operation(P<0.05). The mean VAS scores 1 day and 1, 3, 6, and 12 months after the operation were 3.45±0.47, 2.55±0.60, 1.89±0.48, 1.50±0.27, and 1.12±0.20, respectively. Hollow screw placement combined with percutaneous vertebroplasty serves as a valuable three-column intensive treatment for patients with Kummell's disease and pedicle rupture. This procedure has the advantages of minimal trauma, less pain and quick recovery. The strong anchoring of bone cement and hollow screws provides stable and firm healing conditions for vertebral and pedicle fractures.

Bilateral Lumbar Pedicle Fracture in a Patient Receiving Long-Term Bisphosphonate Therapy: A Case Report

Bilateral Lumbar Pedicle Fracture in a Patient Receiving Long-Term Bisphosphonate Therapy: A Case Report

A predictive model of motor deficit in civilian ballistic lumbosacral spine injuries

BACKGROUND CONTEXTCivilian gunshot wounds to the spine are an increasingly common injury in the USA. A majority of the available research is focused on a military population suffering high energy missile injury. Minimal research has focused on civilian ballistic injuries to the lumbosacral spine as the available studies focus on the entire spine due to limited numbers. PURPOSECharacterize ballistic injuries to the lumbosacral spine and develop a model to predict the presence of neurological deficit based upon a patients presenting fracture morphology. STUDY DESIGNRetrospective chart review. PATIENT SAMPLEOne hundred forty-eight consecutive patients that were presented to an urban level 1 trauma center with ballistic injures to the spine involving the levels L1–S2. OUTCOMES MEASURESNeurological status at presentation and final follow up using the American Spinal Injury Association (ASIA) Impairment Scale. METHODSIRB approval was obtained, and retrospective chart review was performed. Extracted data included patient demographics, neurological status on presentation and final follow-up, fracture morphology, assessment of stability, other associated injuries, and surgical procedures performed. Proportional analysis was performed to characterize the fractures and their associated neurological injuries. Chi-square testing was done to identify fracture characteristics associated with neurologic injury. A multiple logistical regression was performed using fracture characteristics highly associated with neurological deficit to develop a model to predict neurologic deficit. The model was then validated with a receiver operator curve. RESULTSOf the 148 patients, 14 patients underwent spinal surgery with the most common indication being decompression and foreign body removal. There was a high incidence of intra-abdominal injury (73.6%). Fractures were characterized by level, affected vertebral component, and spinal canal involvement. Neurological injury was classified using the ASIA scale at presentation and final follow up. Odds-ratios of vertebral fracture characteristics showed neurologic deficit was highly associated with pedicle fractures (OR=9.07 [4.14–21.54] – 95% CI), lamina fractures (OR=6.42 [3.16–13.62] – 95% CI), facet fractures (OR=5.95 [2.90–12.79] – 95% CI), intra-canal bone (OR=12.79 [5.98–29.05] – 95% CI), and an intra-canal trajectory (OR=1078 [4.48–28.98]) – 95% CI. Multiple logistic regression was performed to construct a predictive model of neurologic deficit which showed that intra-canal trajectory, pedicle fracture and facet fracture are associated with neurologic deficit. An ROC curve was made with an area of 0.849 ([0.7853 to 0.9128 – 95% CI], p<.0001) demonstrating a good model fit. CONCLUSIONSBallistic injuries to the lumbosacral spine involve complex injury patterns in an often polytraumatized patient. Fractures involving the pedicle, lamina, and facet are highly associated with neurologic injury, as is a trans-canal trajectory. A patients fracture morphology can be used to predict if a neurologic deficit is present.

The Biomechanics of the Transpedicular Endoscopic Approach.

Biomechanical cadaveric study. The goal of this study was to analyze the effects of an endoscopic transpedicular approach with different drill diameters (6 and 8mm) and compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle was investigated. Clinical studies have repeatedly highlighted the benefits of endoscopic transpedicular decompression for downmigrated lumbar disc herniations. However, the biomechanical effects on pedicle stability have not been studied up to now. Twenty-four vertebras originating from four fresh-frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the tunneled pedicle on one side, and (2) the native pedicle on the other side. Twelve lumbar vertebrae were assigned to drill diameter of 6mm and the other 12 to diameter of 8mm. The median ratio of sustained force for the operated side compared with the intact contralateral side is equal to 74% (63-88) for both drill diameters combined. An 8mm transpedicular approach recorded an axial resistance of 77% (60-88) compared with the intact contralateral side ( P =0.002). A 6mm approach resulted in an axial resistance of 72% (66-84) compared with the intact opposite side ( P =0.01). No significant difference between the two different drill diameters was recorded ( P =1). For all three subgroups (intact, 8mm, 6mm) the Hounsfield units-values and the absolute resistance force showed significant correlations (intact: ρ=0.859; P <0.001; 8mm: ρ=0.902; P <0.001; 6mm: ρ=0.835; P <0.001). The transpedicular approach significantly reduces the axial resistance force of the pedicle, which may lead to pedicle fracture. Bone quality correlated positively with the absolute resistance force of the pedicle, whereas the influence of the drill hole diameter plays only a limited role.

Bilateral L5 pedicle fracture with L5-S1 spondylolisthesis after single-level L4-5 posterior lumbar interbody fusion: illustrative case.

Single-level posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) is a commonly performed surgical procedure for L4-5 isthmic spondylolisthesis. Postoperative L5 pedicle fracture with rapidly progressive spondylolisthesis at L5-S1 segment after L4-5 PLIF/TLIF is quite rare, and the etiology remains unclear. This report describes this rare complication and proposes a possible etiology focusing on the lumbosacral sagittal imbalance characterized by an anteriorly shifted lumbar loading axis. The authors report a case complicated by L5 bilateral pedicle fractures and rapidly progressive spondylolisthesis at the L5-S1 segment very early after a single-level PLIF for L4-5 isthmic spondylolisthesis. Meyerding grade III anterolisthesis was observed at L5-S1 segment by 3 months after the initial surgery. Additional surgery was performed, and the fixation was extended to L4-ilium. Fracture healing was observed at 6 months postoperatively. This complication may have been caused by abnormal local shear forces on the posterior neural arch of L5 vertebra and L5-S1 intervertebral disc, which were triggered by the fusion surgery for L4 shear-type spondylolisthesis. L4 sagittal vertical axis is considered a reasonable parameter representing lumbosacral sagittal imbalance with an anteriorly shifted loading axis and may be a candidate for the predictive parameters of this rare complication.

Minimally Invasive Fixation in Osteoporotic Vertebral Fractures: A Review Article

here are several surgical strategies which have been proposed to treat the osteoporotic patient with vertebral fracture, ranging from vertebral body cement augmentation, percutaneous/mini-open short segment pedicle screw fixation, and cortical bone trajectory screw to kyphotic deformity correction surgery. Minimally invasive spine surgery has the potential benefits of faster recovery, reduced blood loss, less postoperative wound pain, lower infection risk, and shorter length of hospital stay. Novel surgical techniques such as percutaneous instrumentation fixation, cortical bone trajectory technique, screw cement augmentation, and vertebral body augmentation are developed. However, various complications have been reported, including pedicle fracture, instrumentation loosening, adjacent-level disc degeneration with herniation, and progressive junctional kyphosis. The purpose of this review was to outline various advancements in minimally invasive spinal surgery for patients with osteoporosis. Minimally invasive surgical techniques for fixation including percutaneous instrumentation, cortical bone trajectory technique, screw cement augmentation, and vertebral body augmentation have benefited patient with osteoporosis. Studies and discussions about short-segment pedicle screw fixation (one level above and below the fracture level) have shown that it provides enough stability for thoracolumbar burst fractures. There are also complications, including cement embolism, adjacent vertebral fracture, neuraxial anesthesia, and infection, which have been observed with the above technique. With the advancement of instrument and technique, the complication rate decreased in recent studies. Minimally invasive fixation still has many advantages for patients with osteoporosis. Many of these studies and strategies only have evidence from biomechanical and cadaveric studies and require further clinical trials to establish their clinical efficacy.

Lumbar Pedicle Morphometry of Dry Vertebral Columns in Relation to Transpedicular Fixation: A Cross-Sectional Study From Central India.

The lumbar vertebrae are the largest vertebrae of the vertebral column, which support the maximum body weight. There has been an increased focus on transpedicular spinal fixation for addressing various lumbar spine pathology. However, its safety and efficacy require precise knowledge of the lumbar pedicle anatomy. Mismatched size of screw and pedicle may lead to failure of instrumentation. It may result in cortex perforation or pedicle fracture and loosening of the pedicle screw. The oversizing of the pedicle screw can result in dural tears, leakage of the cerebrospinal fluid, and injuries to the nerve root. As the racial variations in the anatomy of a pedicle are well known, this study was performed to assess the morphological parameters of the lumbar vertebrae pedicles in the Central Indian population so that the appropriate sizes of pedicular implants can be selected. The present study was conducted at a tertiary-level hospital and medical college on dry lumbar vertebrae specimens available in the department of anatomy. The measurement of morphometric parameters of the lumbar vertebrae pedicles was performed in 20 dry lumbar specimens using vernier calipers and a standard goniometer. The morphometric parameters included in the study are pedicle transverse external diameter (pedicle width), pedicle sagittal external diameter (pedicle height), transverse angle of the pedicle, and sagittal angle of the pedicle.Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) system version 25 (Chicago, IL: SPSS Inc.). The broadest external transverse diameter was at the L5 level, with a mean of (17.54±1.6 mm) in the lumbar vertebrae. The broadest external sagittal pedicle diameter was at the L1 level (13.7±0.88 mm). The maximum transverse angle of the pedicle was at L5 with a mean of 25.39±3.10°. The maximum sagittal angle was at L1 with a mean of 5.44±0.71°. The increased concern regarding the internal fixation of the spine with pedicle screw systems created the need to have almost accurate anatomical knowledge of lumbar pedicles. Due to the dynamic nature of the lumbar spine and the body's load, maximum degeneration occurs at this spine segment, making it the most commonly operated region of the vertebral column. In our study, pedicle dimensions are comparable to populations of other Asian countries. However, the pedicle dimension of our population is lower than the White American population. This morphological variation of pedicle anatomy will help surgeons choose appropriate size screws and optimum angulations to insert the implant, decreasing complications.

Four levels pedicle fractures in a renal failure patient: A case report and literature review

Lumbar pedicles are wider than thoracic pedicles and L5 is considered the widest, which requires high-energy trauma to fracture. It is rare to have atraumatic lumbar pedicle fractures. However, it is reported mainly in predisposed patients, like those with contralateral spondylolysis, degenerative spondylolisthesis, previous spine surgery, stressful activities, and metabolic bone disease. We are reporting a rare case of a 37-year-old renal failure male patient who is an office worker who started dialysis only 1 month before the presentation. After a fall from the bed, the patient was found to have four levels pedicle fractures. We aimed to increase the awareness that lumbar pedicle fractures can coexist in patients with renal failure and increase the suspicion index that can promote early diagnosis and effective management.

Image-Guided Percutaneous Multilevel Pediculosynthesis for Treatment of Contiguous Pedicle Stress Fractures: Technical Case Report

Nontraumatic pedicle fracture is uncommon, with sparsely described cases of conservative management versus surgical treatment by open fusion or percutaneous fixation. We report the case of a 60-year-old woman with nontraumatic L4 and L5 pedicle fracture who developed additional pedicle fractures at L3 while undergoing conservative management in a brace. The patient underwent percutaneous pediculosynthesis with screw fixation without fusion at L3-5 bilaterally. The treatment led to fracture healing with good radiographic result and resolution of her symptoms. A trial of conservative management is typically warranted in most cases of nontraumatic pedicle fracture, but there is risk of refractory or progressive symptoms and subsequent fracture. Minimally invasive fixation is a viable surgical option that can be used in multilevel fractures.

PMMA Teeth-Pedicle Screw Spacers in Revision Spinal Surgery: A Technical Note

BACKGROUND Pedicle screw instrumentation was first described by Boucher in 1959 and subsequently popularised by Camille et al. in 1963. It has since become the most prevalent spinal fixation technique with indications for pedicle screw and rod constructs including congenital disease, trauma, infection, and spinal deformity including scoliosis. Initially used in lumbar spine surgery, the use of pedicle screws has since been extended to the thoracic spine where, because of the narrow pedicle corridor and proximity of critical structures, there is less margin for error in screw placement.1 Pedicle screw misplacement has been described in up to 40% of lumbar spine cases and up to 55% in thoracic spine cases.2 Complications associated with pedicle screw placement include damage to spinal cord, neural elements, nerve roots, pedicle fractures, wall cut out, and difficulty fitting instrumentation to the pedicle. Pedicle screw placement techniques can be grossly divided into freehand and image-guided techniques, with freehand techniques including drill assisted and pedicle gearshift (probe) methods while image-guided techniques incorporate fluoroscopic assisted, navigation assisted and robotic-assisted means. Pedicle screw placement into previously fused spines can be challenging with vital anatomic landmarks altered or obscured by the fusion mass.3 PMMA (Polymethyl methacrylate) was first introduced by Charnley in 1960 for cemented total hip arthroplasty. In spine surgery, PMMA has been used in numerous forms including kyphoplasty, disk substitution, and pedicle screw augmentation. In 1972 Bucholz and colleagues began combining PMMA with antibiotics to achieve high local antibiotic concentration in the setting of osteomyelitis; as such PMMA antibiotic loaded spacers have been well described in revision arthroplasty. Staged revision spinal surgery has been advocated by some authors in the setting of deep infection.4 Our senior author has noted that identification of pedicle screw tracts during second stage surgery can be challenging. Rationale We describe a novel surgical technique for the use of PMMA Teeth in the setting of staged revision spinal surgery to maintain the patency of pedicle screw tracts, permitting prompt identification on proceeding surgery stages and achieving local antibiotic delivery when necessary. Surgical Technique A standard posterior approach to the spine is performed identifying the in situ instrumentation. After removal of the in situ spinal rods and pedicle screws, the pedicle screw tracts are examined evaluating the medial, lateral, superior, and inferior walls of the tract. Residual fibrous tissue is debrided. A standard mix of Palacos R cement (Heraeus Medical, Newbury, UK) with the addition of 2 g vancomycin is performed. The PMMA teeth are subsequently fashioned from the Palacos R cement (Fig. 1). Similar to the technique described by Tsung et al.5 in revision hip arthroplasty, the principle for fixation is that of macroscopic fit as opposed to microscopic interlock of the cement; therefore, the PMMA teeth are inserted once the cement has cured.FIGURE 1: PMMA Teeth.PMMA indicates Polymethyl methacrylate.Expected Outcomes The PMMA teeth technique can assist the spinal surgeon in identifying the pedicle screw tract promptly and safely in staged revision spinal surgery with the added benefit of local antibiotic delivery. Complications Potential complications include PMMA Teeth fracture in situ, however, given the PMMA Teeth are inserted once the cement has cured, removal should be uncomplicated. DISCUSSION & CONCLUSION The incidence of revision spinal fusion has a reported range of 8 to 45%, with the revision rate increasing with follow-up; 21% of patients undergoing revision spinal surgery will require further spinal surgery.6 The rate of pedicle screw perforation has been reported to be as high as 28%, and 19% with a perforation greater than 2mm. This poses a significant challenge with considerable potential for pedicle screws to be misplaced in the revision spinal surgery setting.

Biomechanical limitations of partial pediculectomy in endoscopic spine surgery

BACKGROUND CONTEXTTransforaminal endoscopic decompression is an emerging minimally invasive surgical technique in spine surgery. The biomechanical effects and limitations of resections associated with this technique are scarce. PURPOSEThe objective of this study was to analyze the effects of three different extents of reduction at the craniomedial pedicle (10%, 25%, and 50%) and to compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle after reduction was investigated. STUDY DESIGNBiomechanical cadaveric study. METHODSThirty lumbar vertebrae originating from six fresh frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the reduced pedicle on one side, and (2) the native pedicle on the other side. Of the 30 lumbar vertebrae, ten were assigned to each reduction group (10%, 25%, and 50%). RESULTSOn the intact side, the median axial compression force to failure was 593 N (442.4–785.8). A reduction of the pedicle by 10% of the cross-sectional area resulted in a decrease of the axial load resistance by 4% to 66% compared to the intact opposite side (p=.046). The median compression force to failure was 381.89 N (range: 336–662.1). A reduction by 25% resulted in a decrease of 7% to 71% (p=.001). The median compression force to failure was 333 N (265.1–397.3). A reduction by 50% resulted in a decrease of 39% to 90% (p<.001). The median compression force to failure was 200.9 N (192.3–283.9). At 10% pedicle reduction, the Hounsfield units (HU) value and the absolute force required to generate a pedicle fracture showed significant correlations (ρ=.872; p=.001). At 25%, a positive correlation between the two variables could still be identified (ρ=.603; p=.065). At 50%, no correlation was found (ρ=-.122; p=.738). CONCLUSIONResection of the inner, upper part of the pedicle significantly reduces the axial resistance force of the pedicle until a fracture occurs. CLINICAL SIGNIFICANCEThe extent of pedicle reduction itself plays only a limited role: once the cortical bone in the pedicle region is compromised, significant loss of resistance to loading must be anticipated.

Proposal of treatment strategy for pedicle fractures of the C2: An analysis of 49 cases

Proposal of treatment strategy for pedicle fractures of the C2: An analysis of 49 cases

Predictive Markers in Decision-Making for Screwing the Fractured Thoracolumbar Vertebra in the Short-Segment Instrumentation.

In this study, it is aimed to compare the long-term results of patients with short-segment instrumentation where screws were inserted into the fractured vertebra with those of patients with long-segment instrumentation applied by skipping the fractured vertebra and reveal the predictive markers in decision-making for screwing fractured vertebra. Patients were separated into two groups, namely, Group A (patients in which the fractured vertebra and vertebrae above and below the fractured vertebra were screwed (short-segment instrumentation, n=22) and Group B (patients in whom the fractured vertebra was not screwed, whereas two vertebrae above and below the fractured vertebra were screwed (long-segment instrumentation, n=27). The presence of pedicle fracture, AOSpine Classification Scale score, the height of the fractured vertebra, vertebra height below the fractured vertebra, spinal canal diameter, and duration of stay in hospital were different between the groups, preoperatively (p<0.05). Fractured vertebra height, vertebra height below the fractured vertebra, and Karnofsky Performance Scale score were different between the groups in long-term follow-up (p<0.05). The preoperative measurement values were similar to each group's postoperative long-term follow-up results. Logistic regression analysis revealed that the presence of pedicle fracture, AOSpine Classification Scale score, vertebra height below the fractured vertebra, and spinal canal diameter could be the best parameters in decision-making for screwing fractured vertebra (p<0.05). Both instrumentation procedures were observed to have similar effectiveness in preventing a collapse in fractured vertebra during long-term follow-up. It was thought that the AOSpine Classification Scale score, presence of pedicle fracture, vertebra height below the fractured vertebra, and spinal canal diameter could be used as predictive markers in decision-making for screwing fractured vertebrae. Consequently, it was concluded that patients with pedicle fractures, more height loss in the vertebra below the fractured vertebra, and narrow spinal canal would not be suitable for screwing the fractured vertebra.

Surgical management of high-grade lumbar spondylolisthesis associated with Hajdu-Cheney syndrome: illustrative case.

Hajdu-Cheney syndrome (HCS) is a rare connective tissue disorder characterized by severe bone demineralization. In the spine, it is associated with the early onset of severe osteoporosis and can cause spondylolisthesis. Spinal instrumentation in the setting of severe osteoporosis is challenging because of poor resistance of vertebrae to biomechanical stress. A 59-year-old woman with known idiopathic HCS presented with a grade 4 L5-S1 spondylolisthesis and right L5 pedicle fracture associated with a left L5 pars fracture, causing a progressive L5 radiculopathy that was worse on the left side than the right side and bilateral foot drop. The authors performed decompressive lumbar surgery, which included a complete L5 laminectomy and resection of the left L5 pedicle. This was followed by multilevel lumbosacral instrumentation using cement-augmented fenestrated pedicle screws as well as transdiscal sacral screws and bilateral alar-iliac fixation. Postoperatively, the radicular pain resolved, and the left foot drop partially recovered. Stabilization of high-grade spondylolisthesis in the setting of bone demineralization disorders is challenging. The use of different instrumentation techniques is important because it increases biomechanical stability of the overall instrumentation construct.