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

BACKGROUND: 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. OBSERVATIONS: 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. LESSONS: 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.

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

BACKGROUND: Nontraumatic pedicle fracture is uncommon, with sparsely described cases of conservative management versus surgical treatment by open fusion or percutaneous fixation. METHODS: 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. RESULTS: The treatment led to fracture healing with good radiographic result and resolution of her symptoms. CONCLUSIONS: 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.

Risk factors for L5 pedicle fractures after single-level posterior spinal fusion.

BACKGROUND CONTEXT: Pedicle fractures are a rare but potentially devastating complication of posterior instrumented spinal fusion (PSF). Preoperative awareness of the possible risk factors may help prevent these fractures by modifying the surgical plan. However, the risk factors have not yet been identified. PURPOSE: To determine the preoperative parameters associated with postoperative L5 pedicle fracture after L4/5 PSF. STUDY DESIGN: Case control study. PATIENT SAMPLE: Patients undergoing L4/5 PSF at a single academic institution between 2014 and 2020. OUTCOME MEASURES: Occurrence of postoperative L5 pedicle fracture. METHODS: Of 253 patients (female:male, 145:108) undergoing L4/5 PSF from 2014 to 2020, patients with postoperative L5 pedicle fractures were identified retrospectively as "cases" (n = 8, all female, age: 70 ± 10.7 years). As a control group all remaining patients with a follow-up of more than 12 months were allocated (n = 184, 104 females, age: 64.27 ± 13.00 years). In all but 16 cases, anterior support with transforaminal or posterior interbody fusion was performed. Demographic and clinical data (body mass index (BMI)), surgical factors, and comorbidities) were compared. Radiological assessment of spinopelvic parameters was performed using pre- and postoperative standing lateral radiographs. RESULTS: The overall incidence of L5 pedicle fractures after L4/5 spinal fusion was 3.16%, with a median time from index surgery to diagnosis of 25 days (range, 6-199 days) (75% within the first 32 days postoperatively). Patients with L5 pedicle fractures had higher pelvic incidence (PI) (71° ± 9° vs. 56° ± 11°; p=.001), sacral slope (SS) (45° ± 7° vs. 35° ± 8°; p=.002), L5 slope (30° ± 11° vs. 15° ± 10°, p=.001), L5 incidence (42° ± 14° vs. 26° ± 11°; p= .003), L1-S1 lumbar lordosis (LL) postop (57° ± 10° vs. 45° ± 11°; p=.006), and L4 -S1 LL postop (33° ± 7° vs. 28° ± 7°; p=.049) compared with the control group. Pelvic tilt and PI- LL mismatch were not significantly different. Female gender was a significant risk factor for L5 pedicle fractures (p=.015). BMI (kg/m2) was statistically equal in patients with or without pedicle fractures (28.37 ± 5.96 vs. 28.53 ± 16.32; p=.857). There was no significant difference between the groups for approximative bone mineral density assessment (Hounsfield units; 113 ± 60 vs. 120 ± 43; p=.396) using the L3 trabecular region of interest (ROI) measurement. The correlation analysis demonstrated that most of the identified risk factors except for the postoperative L4-S1 lordosis show significant positive associations among each other. All eight patients in the fracture group underwent revision surgery, and the instrumented fusion was extended to the sacrum, with the addition of sacral-alar-iliac or iliac screws, in six cases. CONCLUSIONS: L5 pedicle fractures occurred in 3% of the patients after single level L4/5 PSF. Risk factors are female gender, higher PI, SS, L5 slope, L5 incidence, and LL postop but not high BMI. These findings can be used for surgical planning and decision of fusion levels.

Surgical management of stress fracture of the contralateral pedicle in a baseball player with unilateral lumbar spondylolysis†:†A case report.

We describe successful surgical treatment in a case of L5 unilateral spondylolysis with contralateral pedicle stress fracture that was not resolved by conservative treatment in a high-performing college baseball player. The 20-year-old man presented with left low back pain that stopped his sports activities. Over the previous year, he had experienced a couple of episodes of pain that subsided with cessation of sports but reappeared after a return to sports. Computed tomography and magnetic resonance imaging revealed a right terminal stage pars fracture and a left pedicle stress fracture at L5. The pain originated from the left pedicle fracture, with no pain from the right unilateral spondylolysis. Given that conservative treatment for 1 year had not been effective, we decided on surgical treatment. Bilateral pedicle screws and the smiley face rod method were applied, and both fractures subsequently healed. In the 2 years since the surgery, the patient has returned to sports and has the potential to become a professional player. J. Med. Invest. 67 : 382-385, August, 2020.

Bilateral Acute Osteoporotic Lumbar Pedicle Fracture Presenting with Associated Neurological Deficit: A Case Report and Review of Literature.

Osteoporosis is a common cause of vertebral compression fractures. Often times affecting post-menopausal women, these fractures may occur spontaneously or following minor trauma and are typically managed non-surgically. Here we present a case of a 67-year-old patient who presented with acute compression fracture of the lumbar 5 vertebra and bilateral pedicle fractures of the fourth and fifth lumbar vertebrae following an episode of coughing secondary to tracheitis. She underwent a lumbar 3 to sacral 1/ilium instrumentation/arthrodesis, with screw augmentation via hydroxyapatite, followed by lumbar 4/5 laminectomy and foraminotomy.

Traction screws to reduce a bilateral pedicle fracture of L5: a case report.

Pedicle fractures are rare and usually associated with repetitive stress, high-speed trauma, osteoporosis, unilateral spondylolysis, or instrumentation surgery. A review of the current literature on bilateral pedicle fractures of the lumbar spine revealed only a few cases listed as a complication of instrumentation or excessive decompression surgery. The authors present the clinical case of a 49-year-old man with exacerbating low-back pain and intermittent L5 radicular pain. The known comorbidities were rather remarkable for systemic lupus erythematosus and osteopenia. Radiological investigations revealed an acute bilateral pedicle fracture of L5 without any evidence of preexisting spondylolysis. An off-label minimally invasive fracture reduction and fixation was performed using traction screws and intraoperative navigation. The patient reported instant pain relief and did not show any sensorimotor deficits at discharge. The postoperative CT scan revealed an ossification of the former fracture after 3 months, with great 1-year follow-up outcome. This is the first documented report on the effectiveness of traction screws used in a patient with bilateral pedicle fractures of the L5 vertebra. This minimally invasive technique represents a promising treatment option in selected cases by sparing segmental fusion.

Adjacent Bi-level bilateral pedicle stress fractures after instrumented posterolateral lumbar fusion-a case report and review of the literature.

Isolated bilateral pedicle stress fractures of the lumbar spine are rare events, and few cases are reported in the literature. Their occurrence is commonly related to post-operative complications of spine instrumentation but can also be associated with stress-related activities, degenerative spine conditions, trauma and other miscellaneous causes. The authors report a case of adjacent bi-level bilateral pedicle fracture that developed 5 years after an instrumented posterolateral lumbar fusion. We believe that this has never been described before, and we reviewed the current literature pertaining this subject.

Incidental Idiopathic Bilateral Pedicle Fracture - Case Report and Literature Review.

In rare cases, pedicle fracture is associated with spine surgery, spondylolysis, or stress fracture. We report a patient without trauma whose bilateral lumbar pedicle fracture was detected incidentally. A 67-year-old woman reported leg numbness and pain. Lumbar MRI showed spinal canal stenosis at the L4/L5 level. Drug treatment was only partially effective. A lumbar computed tomography (CT) scan performed 3 months later revealed bilateral pedicle fracture at L4. A second lumbar MRI showed fresh bilateral L4 pedicle fracture that was not observed on the first scan. Due to the presence of osteoporosis we prescribed daily teriparatide and the wearing of a lumbo-sacral corset. Her subsequent clinical course was uneventful and the fractures fused under conservative treatment. During this period, she had no low back pain (LBP). Only 12 earlier patients with spontaneous bilateral pedicle fracture without trauma, spinal surgery, or bone abnormality have been reported. In 8 patients, including ours, the fracture level was at L4. In all except our patient, LBP was the most common symptom. Pedicle fracture as detected incidentally in our patient. Of the 13 patients, 4 were physically active adolescents; of the 9 others, 5 were women with osteoporosis. Our case is the first report of incidental spontaneous bilateral pedicle fracture.

Two-Level Spontaneous Pedicle Fracture above a Degenerative Spondylolisthesis and Minimally Invasive Treatment.

This is a case report and literature review. The objectives of the study are to describe minimally invasive treatment of pedicle fractures, to show contralateral pedicle changes with pedicle fracture treatment, and to review literature on incidence and mechanism of neural arch fractures. After conservative therapy, there are several options for the treatment of pedicle fractures including pediculoplasty, osteosynthesis, or fusion. As patients' age increases, the incidence of pedicle fracture may rise and minimally invasive pedicle screw treatment represents a good motion-preserving option to stabilize without fusion. We report a patient with spontaneous pedicle fractures above a degenerative spondylolisthesis and evidence of contralateral pedicle changes at L2 and L3. After minimally invasive pedicle screw placement, postoperative imaging demonstrated trabeculation across both L2 and L3 fractures with a resolution of contralateral pedicle sclerotic changes and healing of incompletely fracture contralateral pedicle at L2. Pedicle fractures lead to contralateral pedicle sclerotic changes and potential fracture and may cause significant back pain. Stabilization and healing of the neural arch can be achieved with minimally invasive placement of pedicle screws without need for fusion.

Cervical spine fracture through a cervical disc replacement.

INTRODUCTION: We report a rare case of cervical spine trauma through a cervical disc replacement and adjacent multilevel disc fusions. Cervical disc replacement (CDR) is a viable option for the surgical treatment of degenerative disc disease however long term follow up data regarding this operative technique is poor specifically relating to traumatic complications. We know of no previous reports of bilateral cervical pedicle fractures occurring adjacent to CDR and anterior cervical spine instrumentation. PRESENTATION OF CASE: A 46 year-old with a history of C6C7 CDR and C4-6 anterior cervical decompression and fusion was an unrestrained driver involved in a road traffic accident and suffered bilateral C7 pedicle fractures and a right C6C7 facet joint fracture-subluxation without neurological deficit. Reduction and fixation via a posterior approach achieved a satisfactory alignment and the patient made an uneventful recovery. DISCUSSION: A significant force coupled with cervical fixation resulted in a bilateral pedicle fracture of the cervical spine with preserved neurological function. CONCLUSION: The protective role of the CDR has not been previously demonstrated but may have played a role in this case. The authors believe the challenges encountered in the treatment of this patient provide valuable lessons in the management of complex cervical spine trauma in the setting of previous instrumentation.

Pedicle screws with modular head vs. preassembled head used in cortical bone trajectory: Can pars and pedicle fractures be prevented in osteoporotic bone?

Pars and pedicle fractures as a result of CBT (cortical bone trajectory) during pedicle screw placement have been reported. The primary aim of the study is to compare the fracture rate between screws with modular heads to screws with standard pre-assembled tulip heads. The secondary aim of the study is to determine the potential variables that can be identified prior to instrumentation in order to predict risk of fractures. Twenty-four fresh frozen lumbar vertebrae were obtained from five different cadavers. Anatomical landmark measurements were obtained. Right and left pedicles of each vertebra were randomly instrumented with the preassembled head screws (n=24) and modular head screws (n=24) under video recording. X-ray images were obtained for measuring relative angle deviations between tapped and final screw trajectories. Finally, pullout tests were performed. Seventeen out of twenty-four (70.8%) of the spinous processes had to be excised in order to obtain proper trajectories. Six fractures occurred with pre-assembled head screws versus one in the modular head screws (p=0.04). Distances from the midline to the medial wall of the pedicle were marginally significant as a predictor for fracture (p=0.08). The pullout loads between both types of screws were not statistically different (p=0.38). Age was better correlated with pullout load than absolute bone density value (p<0.001). In conclusion, modular head screws had a significantly lower fracture rate than pre-assembled head screws for cortical bone trajectory in osteoporotic bone. There was no clear anatomic variable that could be measured pre-operatively to predict potential fracture risk in CBT.

A rare case of non-traumatic, multi-level, bilateral pedicle fractures of the lumbar spine in a 60-year-old patient.

INTRODUCTION: We report a 60-year-old patient who sustained non-traumatic, multi-level, bilateral lumbar pedicle fractures in the setting of unilateral lumbar spondylolysis. A possible fracture mechanism is evaluated and a review of the literature is presented. Whereas contralateral pedicle fractures of lumbar vertebrae with unilateral spondylosis are well described in young athletes, there is only one case report of multi-level, bilateral pedicle fractures of the lumbar spine in a young patient who sustained a high-impact motorcycle accident. To our knowledge, this is the first report of multi-level, bilateral pedicular fractures of the lumbar spine without a history of trauma. METHODS: The clinical case of a 60-year-old patient with lumbar pain radiating in both legs without antecedent trauma is presented. Besides an idiopathic primary adrenal failure, no further co-morbidities existed. Radiologic investigations showed acute bilateral pedicles' fractures of the lumbar vertebrae two to four (L2-4) and a unilateral spondylolysis L4-5. Dorsoventral instrumentation from L1 to L5 was performed in two steps. RESULTS: The patient had no neurological deficits at discharge. Perioperative cortisol substitution was arranged and continued in the course. At final follow-up after 6 years the patient was pain-free and radiographs confirmed complete fusion of L1-5 with mild degeneration of the adjacent segments. CONCLUSION: The presented fracture pattern has not been described to date. Because of multi-level involvement, instability requiring operative stabilisation was presumed and confirmed during surgery.

Posterior osteosynthesis of a spontaneous bilateral pedicle fracture of the lumbar spine.

Spontaneous bilateral pedicle fractures of the lumbar spine are rare, and an optimal surgical treatment has not been suggested. The authors report the case of a 50-year-old woman who presented with low-back pain and right leg radiating pain of 1 year's duration. Radiological studies revealed a spontaneous bilateral pedicle fracture of L-5. All efforts at conservative treatment failed, and the patient underwent surgery for osteosynthesis of the fractured pedicle using bilateral pedicle screws connected with a bent rod. Her low-back and right leg pain were relieved postoperatively. A CT scan performed 3 months postoperatively revealed the disappearance of the pedicle fracture gap and presence of newly formed bony trabeculation. In rare cases of spontaneous bilateral pedicle fracture of the lumbar spine, osteosynthesis of the fractured pedicle using bilateral pedicle screws and a bent rod is a motion-preserving technique that may be an effective option when conservative management has failed.

Pars and pedicle fracture and screw loosening associated with cortical bone trajectory: a case series and proposed mechanism through a cadaveric study.

BACKGROUND CONTEXT: Cortical bone trajectory (CBT) technique for pedicle screw placement in the lumbar spine has become more popular since its introduction in 2009. The distinct advantages of using the CBT technique involve increased screw purchase within the cortical bone and reduced surgical dissection. However, contrary to several favorable biomechanical results, there were anecdotal reports of clinical complications associated with CBT. PURPOSE: This study aimed (1) to report on two unique pars and pedicle fracture cases involving the use of the CBT technique and (2) to perform a cadaveric pilot study to determine the possible mechanism for this fracture pattern. STUDY DESIGN/SETTING: A case report and cadaveric study were carried out. METHODS: After presenting two clinical cases, 19 fresh-frozen lumbar vertebrae were obtained from 8 cadavers. Pedicle screws were instrumented on each level using CBT under video recording. After the instrumentation, X-ray images were obtained, and anatomical dissections were performed. RESULTS: To be able to reach a necessary angle for medial to lateral CBT trajectory, 13 out of 19 (68%) spinous processes had to be removed. There were a total of seven complications. One pars and pedicle fracture out of 37 trajectories (2.7%) and 6 out of 37 trajectory deviations (16.2%), which resulted in gross loosening, were observed. CONCLUSIONS: The head of the pedicle screw impinging on the base of spinous process and lamina was observed in our cadaveric model. This mechanism could potentially explain both screw loosening and fractures associated with the CBT technique.

Spondylolisthesis accompanying bilateral pedicle stress fracture at two vertebrae.

There has been no report of bilateral pedicle stress fractures involving two vertebrae. The authors describe a unique case of spondylolisthesis accompanying a bilateral pedicle stress fracture involving two vertebrae. De novo development of spondylolisthesis at the L5-S1 vertebrae accompanying a bilateral pedicle stress fracture at L4 and L5 was observed in a 70-year-old woman. The patient's medical history was unremarkable and she did not have any predisposing factors except severe osteoporosis. Interbody fusion with bone cement augmented screw fixation was performed. Surgical treatment resulted in good pain management and improved functional recovery.