Incidence of Osteoporosis-Related Complications Following Posterior Lumbar Fusion.

STUDY DESIGN: Retrospective review. OBJECTIVES: This study investigates the prevalence of adverse postsurgical events, or osteoporosis-related complications (ORCs), following spinal fusion. METHODS: Patients undergoing primary posterior thoracolumbar or lumbar fusion by 1 of 2 surgeons practicing at a single institution were analyzed from 2007 to 2014. ORCs were defined in one of the following categories: revision surgery, compression fracture, proximal junctional kyphosis, pseudarthrosis, or failure of instrumentation. Patients with a bone mineral density of the hips and/or spine performed within 1 year of the index procedure were included. Patients were stratified into normal bone density, osteopenia, and osteoporosis using WHO guidelines. Patients were excluded if they were younger than 18 years at the time of surgery, with infection, malignancy, skeletal dysplasia, neuromuscular disorders, concomitant or staged anterior-posterior procedure, or fusion performed because of trauma. RESULTS: Out of 140 patients included, the prevalence of normal bone density was 31.4% (44/140), osteopenia 58.6% (82/140), and osteoporosis 10.0% (14/140). There were no differences between groups for gender, age, body mass index, and interbody device rate. The overall prevalence of ORCs was 32.1% (45/140). By group, there was a prevalence of 22.7% (10/44), 32.9% (27/82), and 50.0% (7/14) for normal bone density, osteopenia, and osteoporosis, respectively. These differences were significantly higher for both the osteopenia and osteoporosis groups. CONCLUSIONS: Patients with T scores below -1.0 undergoing posterior lumbar fusion have an increased prevalence of ORCs. Consideration of bone density plays a crucial role in patient selection, medical management, and counseling patient expectations.

Postoperative pain following posterior iliac crest bone graft harvesting in spine surgery: a prospective, randomized trial.

BACKGROUND CONTEXT: Postoperative pain at the site of bone graft harvest for posterior spine fusion is reported to occur in 6%-39% of cases. However, the area around the posterior, superior iliac spine is a frequent site of referred pain for many structures. Therefore, many postoperative spine patients may have pain in the vicinity of the posterior iliac crest that may not in fact be caused by bone graft harvesting. The literature may then overestimate the true incidence of postoperative iliac crest pain. PURPOSE: We performed a prospective study testing the hypothesis that patients will not report significantly higher visual analog scores over the graft harvest site when compared with the contralateral, non-harvested side. STUDY DESIGN/SETTING: This is a prospective, randomized cohort study. PATIENT SAMPLE: Patients aged 18-75 years undergoing elective spinal fusion of one to two levels between L4 and S1 for spinal stenosis and spondylolisthesis were randomized to left-sided or right-sided iliac crest bone graft (ICBG) donor sites and blinded to the side of harvest. OUTCOME MEASURES: Primary outcome was a 10-point visual analog scale (VAS) for pain over the left and right posterior superior iliac spine. METHODS: Bone graft was harvested via spinal access incisions without making a separate skin incision over the crest. Each patient's non-harvested side served as an internal control. Data points were recorded by patients on their study visit sheets preoperatively and at 6 weeks, 3 months, 6 months, and 1 year postoperatively. RESULTS: Forty patients were enrolled in the study (23 females) with an average follow-up of 8.1 months (1.5-12 months). Mean age was 51.7 years (23-77 years). Left- and right-side ICBG harvesting was performed equally between the 40 patients. The average volume of graft harvested from the left was 35.3 mL (15-70 mL) and 36.1 mL (15-60 mL) from the right. There was no statistical difference between preoperative VAS score on the harvested side compared with the non-harvested side (p=.415). Postoperatively, there were consistently higher VAS scores on the operative side; however, these differences were not statistically significant at 6 weeks (p=.111), 3 months (p=.440), 6 months (p=.887), or 12 months (p=.240). Both groups did, however, show statistically significant improvements in VAS scores over time within the operative and nonoperative sides (p<.05). Graft volume had no effect on the VAS scores (p=.382). CONCLUSIONS: The current literature does not adequately illuminate the incidence of postoperative pain at the site of harvest and the relative magnitude of this pain in comparison with the patient's residual low back pain. This is the first study to blind the patient to the laterality of bone graft harvesting. Our randomized investigation showed that although pain on the surgical side was slightly higher, it was neither clinically nor statistically different from the nonsurgical side. Our conclusion supports surgeons' use of autologous bone graft, which offers a cost-effective, efficacious spinal fusion supplement.

Prognosis of Significant Intraoperative Neurophysiologic Monitoring Events in Severe Spinal Deformity Surgery.

BACKGROUND: Intraoperative neurophysiologic monitoring has become a standard tool for mitigating neurologic injury during spinal deformity surgery. Significant monitoring changes during deformity correction are relatively uncommon. This study characterizes precipitating factors for neurologic injury and relates significant events and postoperative neurologic prognosis. METHODS: All spinal deformity surgeries at a West African hospital over a 12-month period were reviewed. Patients were included if complete operative reports, monitoring data, and postoperative neurologic examinations were available for review. Surgical and systemic triggers of monitoring events were recorded and neurologic status was followed for 6 weeks postoperatively. RESULTS: Eighty-eight patients met inclusion criteria. The average age was 14 years (3-28). The average kyphosis was 108° (54°-176°) and average scoliosis was 100° (48°-177°). There were 44 separate neurologic events in 34 patients (39%). The most common triggers were traction or positioning (16), posterior column osteotomies/vertebral column resections (9/1), and distraction, corrective maneuvers, or implant placement (12). On surgery completion, 100% (12/12) of events from non-osteotomy-related surgical procedures, 75% (12/16) of events from traction or positioning resolved; however, 0% (0/10) of events from osteotomies resolved completely. Eight percent (7/88) had new neurologic deficits postoperatively, all with intraoperative monitoring changes. In 6 of these 7 patients, the event was attributed to an osteotomy; in 1 patient the cause was not determined. At 6-week follow-up, all patients had some preserved motor function bilaterally with the ability to walk (ASIA D/E) or recovered completely. CONCLUSIONS: Intraoperative signal changes were most frequently from traction or positioning. However, the most common cause of persistent neurologic deterioration and the only cause of postoperative neurologic deficit was the performance of osteotomies. Unlike traction- or instrument-related correction, osteotomies produce irreversible changes, from canal intrusion or sudden localized deformity change. The incidence of postoperative neurologic deficit is very low when the inciting cause is reversed; however, osteotomy-related events are irreversible, with a high incidence of associated lasting neurologic injury.

Does adolescent obesity affect surgical presentation and radiographic outcome for patients with adolescent idiopathic scoliosis?

The purpose of this study was to test a hypothesis that overweight patients with adolescent idiopathic scoliosis present with larger curves and achieve less surgical correction than do healthy weight counterparts. A total of 251 individuals were grouped by BMI into overweight (BMI% ≥85) and healthy weight (BMI% <85) groups. Overweight patients demonstrated significantly larger intraoperative blood loss (P=0.041), although there was no significant difference in the number of intraoperative transfusions. Major curves and surgical correction were similar between the two groups. A greater postoperative thoracic kyphosis at latest follow-up may suggest a worsening sagittal profile in these individuals postoperatively.

Maintenance of Derotation in Adolescent Idiopathic Scoliosis: a Novel Technique Measuring Postoperative Vertebral Rotation by Pedicle Screw Position.

BACKGROUND: Current methods of measuring vertebral rotation by plain radiographs rely on anatomic landmarks that are not present in the postoperative spine or require advanced imaging. Furthermore, there are few studies on the incidence of crankshaft with modern pedicle instrumentation. QUESTIONS/PURPOSES: We sought to (1) describe and validate a method of vertebral rotation measurement using plain radiographs and (2) measure postoperative rotation in a series of patients treated for adolescent idiopathic scoliosis. METHODS: Patients with adolescent idiopathic scoliosis treated with surgery over a 6-year period were reviewed. Patients with computed tomography (CT) scans and radiographs within 60 days of another were included. Vertebral rotation was calculated by radiographic measurements and measured directly by CT scan. As an internal control, patients with two apical pedicle screws on all radiographs were analyzed. Rotation was measured for all patients with at least 1 year of radiographic follow-up. RESULTS: Three thousand five hundred fifty-two instrumented spinal levels in 308 consecutive patients were reviewed. Ten patients with 93 screws were analyzed by CT and radiographs. The average discrepancy between computed tomography (CT) and radiographs was 3.3 ± 1.9°, with 81.7% (76/93) within 5°. Intra- and inter-rater reliabilities for measured axial rotation were excellent (intra-class correlation coefficient (ICC) = 0.879 and 0.900, respectively). One hundred swventy-eight patients were eligible with an average follow-up of 2.3 ± 1.2 years; 84.8% (151/178) had screw(s) visible on all images at the major curve apex. The average postsurgical rotation was 3.5 ± 2.9°; 19.2% (29/151) were measured to have a rotation over 5°, and 4.0% (6/151) demonstrated a rotation over 10°. Only 4.6% (7/151) of patients demonstrated a postoperative Cobb angle change over 10°. CONCLUSIONS: Most major curves have apical pedicle screw instrumentation that can be followed by radiographs alone to measure rotation. Vertebral rotation measurement requires only plain radiographs and is a more sensitive determination for subtle postoperative crankshaft than change in Cobb angle.

Do Current Recommendations for Upper Instrumented Vertebra Predict Shoulder Imbalance? An Attempted Validation of Level Selection for Adolescent Idiopathic Scoliosis.

BACKGROUND: Shoulder balance for adolescent idiopathic scoliosis (AIS) patients is associated with patient satisfaction and self-image. However, few validated systems exist for selecting the upper instrumented vertebra (UIV) post-surgical shoulder balance. QUESTIONS/PURPOSES: The purpose is to examine the existing UIV selection criteria and correlate with post-surgical shoulder balance in AIS patients. METHODS: Patients who underwent spinal fusion at age 10-18 years for AIS over a 6-year period were reviewed. All patients with a minimum of 1-year radiographic follow-up were included. Imbalance was determined to be radiographic shoulder height |RSH| ≥ 15 mm at latest follow-up. Three UIV selection methods were considered: Lenke, Ilharreborde, and Trobisch. A recommended UIV was determined using each method from pre-surgical radiographs. The recommended UIV for each method was compared to the actual UIV instrumented for all three methods; concordance between these levels was defined as "Correct" UIV selection, and discordance was defined as "Incorrect" selection. RESULTS: One hundred seventy-one patients were included with 2.3 ± 1.1 year follow-up. For all methods, "Correct" UIV selection resulted in more shoulder imbalance than "Incorrect" UIV selection. Overall shoulder imbalance incidence was improved from 31.0% (53/171) to 15.2% (26/171). New shoulder imbalance incidence for patients with previously level shoulders was 8.8%. CONCLUSIONS: We could not identify a set of UIV selection criteria that accurately predicted post-surgical shoulder balance. Further validated measures are needed in this area. The complexity of proximal thoracic curve correction is underscored in a case example, where shoulder imbalance occurred despite "Correct" UIV selection by all methods.