David Ibrahimi

Moyamoya disease in children

PurposeMoyamoya disease, a rare cause of pediatric stroke, is a cerebrovascular occlusive disorder resulting from progressive stenosis of the distal intracranial carotid arteries and their proximal branches. In response to brain ischemia, there is the development of basal collateral vessels, which give rise to the characteristic angiographic appearance of moyamoya. If left untreated, the disease can result in overwhelming permanent neurological and cognitive deficits.MethodsWhereas moyamoya disease refers to the idiopathic form, moyamoya syndrome refers to the condition in which children with moyamoya also have a recognized clinical disorder. As opposed to adults who typically present in the setting of intracranial hemorrhage, the classic pediatric presentation is recurrent transient ischemic attacks and/or completed ischemic strokes.ResultsSurgical revascularization, including direct and indirect techniques, remains the mainstay of treatment, and has been shown to improve long-term outcome in children with moyamoya.ConclusionThe authors discuss the diagnosis and treatment of moyamoya disease in the pediatric population.

Biomechanical fixation properties of cortical versus transpedicular screws in the osteoporotic lumbar spine: an in vitro human cadaveric model

OBJECTIVE Optimal strategies for fixation in the osteoporotic lumbar spine remain a clinical issue. Classic transpedicular fixation in the osteoporotic spine is frequently plagued with construct instability, often due to inadequate cortical screw-bone purchase. A cortical bone trajectory maximizes bony purchase and has been reported to provide increased screw pullout strength. The aim of the current investigation was to evaluate the biomechanical efficacy of cortical spinal fixation as a surgical alternative to transpedicular fixation in the osteoporotic lumbar spine under physiological loading. METHODS Eight fresh-frozen human spinopelvic specimens with low mean bone mineral densities (T score less than or equal to -2.5) underwent initial destabilization, consisting of laminectomy and bilateral facetectomies (L2-3 and L4-5), followed by pedicle or cortical reconstructions randomized between levels. The surgical constructs then underwent fatigue testing followed by tensile load to failure pullout testing to quantify screw pullout force. RESULTS When stratifying the pullout data with fixation technique and operative vertebral level, cortical screw fixation exhibited a marked increase in mean load at failure in the lower vertebral segments (p = 0.188, 625.6 ± 233.4 N vs 450.7 ± 204.3 N at L-4 and p = 0.219, 640.9 ± 207.4 N vs 519.3 ± 132.1 N at L-5) while transpedicular screw fixation demonstrated higher failure loads in the superior vertebral elements (p = 0.024, 783.0 ± 516.1 N vs 338.4 ± 168.2 N at L-2 and p = 0.220, 723.0 ± 492.9 N vs 469.8 ± 252.0 N at L-3). Although smaller in diameter and length, cortical fixation resulted in failures that were not significantly different from larger pedicle screws (p > 0.05, 449.4 ± 265.3 N and 541.2 ± 135.1 N vs 616.0 ± 384.5 N and 484.0 ± 137.1 N, respectively). CONCLUSIONS Cortical screw fixation exhibits a marked increase in mean load at failure in the lower vertebral segments and may offer a viable alternative to traditional pedicle screw fixation, particularly for stabilization of lower lumbar vertebral elements with definitive osteoporosis.

Operative and Nonoperative Treatment Approaches for Lumbar Degenerative Disc Disease Have Similar Long-Term Clinical Outcomes Among Patients with Positive Discography

OBJECTIVE It remains unclear whether fusion for lumbar degenerative disc disease with positive discography produces better outcomes compared with nonoperative treatment. The aim of this study was to compare outcomes of patients with discography-concordant lumbar degenerative disc disease electing for fusion versus nonoperative treatment. METHODS We retrospectively reviewed consecutive patients with back pain and concordant lumbar discogram who were offered fusion. Follow-up questionnaires included pain score, Oswestry disability index, short form-12, and satisfaction scale. Patients were stratified based on whether they elected for fusion or nonoperative treatment. RESULTS Overall follow-up was 48% (96/200). Patients lacking follow-up were slightly older (P = 0.021) and less likely to be smokers (P = 0.013). Between patients with and without follow-up, there were no significant differences in pain score at initial visit, body mass index, or gender (P ≥ 0.40). The 96 patients for whom follow-up was obtained included 53 in the operative and 43 in the nonoperative groups. At baseline, there were no significant differences between these groups based on age, pain score, body mass index, smoking, or gender (P ≥ 0.25). Mean follow-up was 63 months for operative and 58 months for nonoperative patients (P = 0.20). The mean pain score at last follow-up improved significantly for operative and nonoperative patients (P < 0.001). At follow-up, operative and nonoperative groups did not differ significantly with regard to pain scores, Oswestry disability index, short form-12, or satisfaction scale. CONCLUSIONS Comparison of long-term outcomes for patients with back pain and concordant discography did not demonstrate a significant difference in outcome measures of pain, health status, satisfaction, or disability based on whether the patient elected for fusion or nonoperative treatment.

A Multi-Center Evaluation of Clinical and Radiographic Outcomes Following High-Grade Spondylolisthesis Reduction and Fusion.

Objective: A retrospective review of the clinical and radiographic outcomes from a multicenter study of surgical treatment for high-grade spondylolisthesis (HGS) in adults. The objective was to assess the safety of surgical reduction, its ability to correct regional deformity, and its clinical effectiveness. Methods: Retrospective, multicenter review of adults (age above 18 y) with lumbosacral HGS (Meyerding grade 3–5) treated surgically with open decompression, attempted reduction, posterior instrumentation, and interbody fusion. Preoperative and postoperative assessment of the Meyerding grade, slip angle, and sacral inclination were performed based on standing radiographs. Preoperative visual analog scale scores were compared with those at the mean follow-up period. Prolo and Oswestry Disability Index scores at most recent follow-up were assessed. Results: A total of 25 patients, aged 19–72 years, met inclusion criteria. Seventeen interbody cages were placed, including 15 transforaminal lumbar interbody fusions, 1 posterior lumbar interbody fusion, and 1 anterior lumbar interbody fusion. Five patients required sacral dome osteotomies. The average follow-up was 21.3 months. At most recent follow-up there was a statistically significant improvement in both the Meyerding grade and the slip angle (P<0.05). There was 1 intraoperative complication resulting in a neurological deficit (4%) and 1 intraoperative vertebral body fracture (4%). No additional surgery was required for any of these patients. There were no cases of nonunion or device failure except for 1 patient who suffered an unrelated traumatic injury 1 year after surgery. The mean Oswestry Disability Index and Prolo scores at mean follow-up of 21.3 months were 20% (minimum disability) and 8.2 (grade 1), respectively. Conclusions: The present study suggests that reduction, when accomplished in conjunction with wide neural element decompression and instrumented arthrodesis, is safe, effective, and durable with low rates of neurological injury, favorable clinical results, and high-fusion rates.

Pedicle Subtraction Osteotomy

Pedicle subtraction osteotomy (PSO) is a surgical procedure that can be used to help correct fixed sagittal plane deformities. These deformities may have a variety of etiologies, including degenerative, posttraumatic, neoplastic, infectious, metabolic, and congenital disorders [1–3]. The aging population and rising expectations for quality of life are leading to increasing numbers of patients seeking medical and surgical evaluation for symptomatic fixed sagittal deformity. With the advent of polysegmental three-column fixation with pedicle screws and advances in spinal instrumentation, posterior-only approaches for correcting kyphotic or kyphoscoliotic deformities have become feasible and more common in recent years, avoiding the need of anterior approaches [4]. The use of posterior-only osteotomies with pedicle screw instrumentation can provide significant alignment correction in all three dimensions, whereas greater pedicle screw pullout strength and stiffness limit the number of levels fused, allowing for preservation of more mobile spinal segment [4, 5].