Single position robot-assisted pedicle screw placement with S2-alar-iliac fixation in lateral decubitus: cadaveric feasibility study and early clinical experience.

OBJECTIVES: Single position lateral fusion with robotic assistance eliminates the need for surgical staging while harnessing the precision of robotic adjuncts. We expand on this technique by demonstrating the technical feasibility of placing bilateral pedicle screws with S2-alar-iliac (S2AI) fixation while in the lateral position. METHODS: A cadaveric study was performed using 12 human specimens. A retrospective clinical series was also performed for patients who had undergone robot-assisted placement of S2AI screws in lateral decubitus between June 2020 and June 2022. Case demographics, implant placement time, implant size, screw accuracy, and complications were recorded. Early postoperative radiographic outcomes were reported. RESULTS: In the cadaveric series, a total of 126 screws were placed with robotic assistance in 12 cadavers of which 24 screws were S2AI. There were four breaches from pedicle screws and none with S2AI screws for an overall accuracy rate of 96.8%. In the clinical series, four patients (all male, mean age 65.8 years) underwent single position lateral surgery with S2AI distal fixation. Mean BMI was 33.6 and mean follow-up was 20.5 months. Mean radiographic improvements were lumbar lordosis 12.3 ± 4.7°, sagittal vertical axis 1.5 ± 2.1 cm, pelvic tilt 8.5 ± 10.0°, and pelvic incidence-lumbar lordosis mismatch 12.3 ± 4.7°. A total of 42 screws were placed of which eight screws were S2AI. There were two breaches from pedicle screws and none from S2AI screws for an overall accuracy rate of 95.2%. No repositioning or salvage techniques were required for the S2AI screws. CONCLUSIONS: We demonstrate here the technical feasibility of single position robot-assisted placement of S2-alar-iliac screws in the lateral decubitus position for single position surgery.

Management of Giant Sacral Pseudomeningocele in Revision Spine Surgery.

BACKGROUND: Giant pseudomeningoceles are an uncommon complication of spine surgery. Surgical management and extirpation can be difficult, and guidelines remain unclear. METHODS: Here, we present a 56-year-old female patient with a history of grade III L5-S1 spondylolisthesis who was treated with 2 prior spine surgeries. The patient was treated with bone grafting for pseudarthrosis and instrumentation from L4 to ilium. After unsuccessful intraoperative and postoperative cerebrospinal fluid drainage and dural repair, the patient presented to the emergency room with debilitating positional headaches. RESULTS: The patient underwent dural repair with bovine pericardial patch inlay sutured with 7-0 prolene, blood patch, and a dural sealant. Plastic surgery performed a layered closure, using acellular dermal matrix over the dural closure. The bilateral paraspinal flaps were advanced medially to cover the entirety of the acellular dermal matrix, and the fasciocutaneous flaps were then advanced to the midline for a watertight closure. At 3-month follow-up, the patient was headache free and had returned to her activities of daily living. CONCLUSIONS: We conclude that early consultation with plastic surgery can be greatly beneficial to effectively extirpate dead space and resolve giant sacral pseudomeningoceles, especially if there is concern of persistent cerebrospinal fluid leakage due to relatively immobile avascular soft tissue as a result of prior revision surgery.

Engorged venous plexus mimicking adjacent segment disease: Case report and review of the literature.

BACKGROUND: An engorged venous plexus may mimic nerve compression from a herniated disk on the magnetic resonance (MR) studies as they both have similar signal intensities. During a laminectomy, if an engorged venous plexus is encountered instead of a disk herniation, there may be marked unanticipated bleeding. CASE DESCRIPTION: A 58-year-old female who had a prior anterior lumbar interbody fusion later returned with recurrent radiculopathy. Adjacent segment disease from a spinal disk herniation was suspected based on the surgical history, physical examination, and imaging (MRI) findings. Rather than a disk, an engorged venous plexuses (EVP) was encountered intraoperatively. CONCLUSION: Here, we discussed our findings regarding a lumbar EVP rather than a herniated disk and reviewed the current literature. Although rare, a higher index of suspicion for these vascular malformations based on combined historical information and MRI studies should allow one to better detect and/or anticipate an EVP rather than a routine disk.

Decompression Surgery versus Interspinous Devices for Lumbar Spinal Stenosis: A Systematic Review of the Literature.

In this retrospective review study, the authors systematically reviewed the literature to elucidate the efficacy and complications associated with decompression and interspinous devices (ISDs) used in surgeries for lumbar spinal stenosis (LSS). LSS is a debilitating condition that affects the lumbar spinal cord and spinal nerve roots. However, a comprehensive report on the relative efficacy and complication rate of ISDs as they compare to traditional decompression procedures is currently lacking. The PubMed database was queried to identify clinical studies that exclusively investigated decompression, those that exclusively investigated ISDs, and those that compared decompression with ISDs. Only prospective cohort studies, case series, and randomized controlled trials that evaluated outcomes using the Visual Analog Scale (VAS), Oswestry Disability Index, or Japanese Orthopedic Association scores were included. A random-effects model was established to assess the difference between preoperative and the 1-2-year postoperative VAS scores between ISD surgery and lumbar decompression. This study included 40 papers that matched our criteria. Twenty-five decompression-exclusive clinical trials with 3,386 patients and a mean age of 68.7 years (range, 31-88 years) reported a 2.2% incidence rate of dural tears and a 2.6% incidence rate of postoperative infections. Eight ISD-exclusive clinical trials with 1,496 patients and a mean age of 65.1 (range, 19-89 years) reported a 5.3% incidence rate of postoperative leg pain and a 3.7% incidence rate of spinous process fractures. Seven studies that compared ISDs and decompression in 624 patients found a reoperation rate of 8.3% in ISD patients vs. 3.9% in decompression patients; they also reported dural tears in 0.32% of ISD patients vs. 5.2% in decompression patients. A meta-analysis of the randomized controlled trials found that the differences in preoperative and postoperative VAS scores between the two groups were not significant. Both decompression and ISD interventions are unique surgical interventions with different therapeutic efficacies and complications. The collected studies do not consistently demonstrate superiority of either procedure over the other but understanding the differences between the two techniques can help tailor treatment regimens for patients with LSS.

Use of a Reverse Bohlman Technique for Low-Grade Spondylolisthesis.

BACKGROUND: Treatment of spondylolisthesis can be difficult with regard to patients with high sacral slopes that may prohibit placement of interbody grafts for fusions across that segment. Here, we describe placement of a reverse Bohlman technique from an anterior approach to obtain fusion across a low-grade spondylolisthesis with a high sacral slope to obtain anterior fusion. METHODS: A chart review was conducted on this single patient regarding his clinical course and outcome. RESULTS: A 54-year-old male presented with low-back pain associated with bilateral leg pain dating back several years. Plain films demonstrated a Grade II isthmic spondylolisthesis at L5-S1 with spinopelvic measurements of 73° sacral slope, 82° lumbar lordosis, 12° pelvic tilt, and 94° pelvic incidence. Magnetic resonance imaging showed bilateral L5 pars defects with diffuse degenerative disease from L4 through S1 and significant ligamentous and facet hypertrophy. He underwent an L4-5 anterior lumbar interbody fusion and an L5-S1 reverse Bohlman placement of a transvertebral transsacral titanium mesh cage. This was supplemented with a posterior decompression and instrumentation from L4-ilium. He had resolution of his radiculopathy and has maintained a good clinical outcome at 3 years follow up. CONCLUSIONS: We present here a patient with low-grade spondylolisthesis and a steep sacral slope who underwent a successful reverse Bohlman approach with long-term follow up. This report highlights the potential utility of this method as a viable alternative for patients with low-grade spondylolisthesis. LEVEL OF EVIDENCE: IV. CLINICAL RELEVANCE: Technical description of surgical technique.

Bilateral Vertebral Artery Occlusion After Cervical Spine Fracture Dislocation.

BACKGROUND: Vertebral artery injury is known to potentially occur in conjunction with blunt cervical spine trauma. Rarely, these injuries present bilaterally as complete occlusions. Twelve cases of bilateral vertebral artery occlusions after closed cervical spine trauma have been described in the reported data, nearly all of which demonstrated signs and symptoms of vertebrobasilar insufficiency and ischemia. CASE DESCRIPTION: Our patient presented after a traumatic C5-C6 flexion-distraction injury that had resulted in bilateral locked facets and spinal cord injury and bilateral vertebral artery occlusions at the V1 segment. However, our patient did not show any cranial symptoms despite his neurovascular injury. CONCLUSIONS: We present our patient's case as a rare illustration of a bilateral vertebral artery occlusion after blunt cervical spine trauma without clinical vertebrobasilar ischemic sequelae.