Assessment of Surgical Procedural Time, Pedicle Screw Accuracy, and Clinician Radiation Exposure of a Novel Robotic Navigation System Compared With Conventional Open and Percutaneous Freehand Techniques: A Cadaveric Investigation.

STUDY DESIGN: Cadaveric study. OBJECTIVE: To evaluate accuracy, radiation exposure, and surgical time of a new robotic-assisted navigation (RAN) platform compared with freehand techniques in conventional open and percutaneous procedures. METHODS: Ten board-certified surgeons inserted 16 pedicle screws at T10-L5 (n = 40 per technique) in 10 human cadaveric torsos. Pedicle screws were inserted with (1) conventional MIS technique (L2-L5, patient left pedicles), (2) MIS RAN (L2-L5, patient right pedicles), (3) conventional open technique (T10-L1, patient left pedicles), and (4) open RAN (T10-L1, patient right pedicles). Output included (1) operative time, (2) number of fluoroscopic images, and (3) screw accuracy. RESULTS: In the MIS group, compared with the freehand technique, RAN allowed for use of larger screws (diameter: 6.6 ± 0.6 mm vs 6.3 ± 0.5 mm; length: 50.3 ± 4.1 mm vs 46.9 ± 3.5 mm), decreased the number of breaches >2 mm (0 vs 7), fewer fluoroscopic images (0 ± 0 vs 108.3 ± 30.9), and surgical procedure time per screw (3.6 ± 0.4 minutes vs 7.6 ± 2.0 minutes) (all P < .05). Similarly, in the open group, RAN allowed for use of longer screws (46.1 ± 4.1 mm vs 44.0 ± 3.8 mm), decreased the number of breaches >2 mm (0 vs 13), fewer fluoroscopic images (0 ± 0 vs 24.1 ± 25.8) (all P < .05), but increased total surgical procedure time (41.4 ± 8.8 minutes vs 24.7 ± 7.0 minutes, P = .000) while maintaining screw insertion time (3.31.4 minutes vs 3.1 ± 1.0 minutes, P = .650). CONCLUSION: RAN significantly improved accuracy and decreased radiation exposure in comparison to freehand techniques in both conventional open and percutaneous surgical procedures in cadavers. RAN significantly increased setup time compared with both conventional procedures.

PEEK versus titanium cages in lateral lumbar interbody fusion: a comparative analysis of subsidence.

OBJECTIVE: The authors have provided a review of radiographic subsidence after lateral lumbar interbody fusion (LLIF) as a comparative analysis between titanium and polyetheretherketone (PEEK) cages. Many authors describe a reluctance to use titanium cages in spinal fusion secondary to subsidence concerns due to the increased modulus of elasticity of metal cages. The authors intend for this report to provide observational data regarding the juxtaposition of these two materials in the LLIF domain. METHODS: A retrospective review of a prospectively maintained database identified 113 consecutive patients undergoing lateral fusion for degenerative indications from January to December 2017. The surgeons performing the cage implantations were two orthopedic spine surgeons and two neurosurgeons. Plain standing radiographs were obtained at 1-2 weeks, 8-12 weeks, and 12 months postoperatively. Using a validated grading system, interbody subsidence into the endplates was graded at these time points on a scale of 0 to III. The primary outcome measure was subsidence between the two groups. Secondary outcomes were analyzed as well. RESULTS: Of the 113 patients in the sample, groups receiving PEEK and titanium implants were closely matched at 57 and 56 patients, respectively. Cumulatively, 156 cages were inserted and recombinant human bone morphogenetic protein-2 (rhBMP-2) was used in 38.1%. The average patient age was 60.4 years and average follow-up was 75.1 weeks. Subsidence in the titanium group in this study was less common than in the PEEK cage group. At early follow-up, groups had similar subsidence outcomes. Statistical significance was reached at the 8- to 12-week and 52-week follow-ups, demonstrating more subsidence in the PEEK cage group than the titanium cage group. rhBMP-2 usage was also highly correlated with higher subsidence rates at all 3 follow-up time points. Age was correlated with higher subsidence rates in univariate and multivariate analysis. CONCLUSIONS: Titanium cages were associated with lower subsidence rates than PEEK cages in this investigation. Usage of rhBMP-2 was also robustly associated with higher endplate subsidence. Each additional year of age correlated with an increased subsidence risk. Subsidence in LLIF is likely a response to a myriad of factors that include but are certainly not limited to cage material. Hence, the avoidance of titanium interbody implants secondary solely to concerns over a modulus of elasticity likely overlooks other variables of equal or greater importance.

Adjacent Segment Pathology After Treatment With Cervical Disc Arthroplasty or Anterior Cervical Discectomy and Fusion, Part 1: Radiographic Results at 7-Year Follow-Up.

BACKGROUND: Adjacent segment pathology (ASP) remains a concern following treatment with cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF). Radiographic ASP (RASP) is ASP identified on imaging, which may or may not include clinical symptoms. The risk factors for development of RASP and its clinical effects remain controversial. In part 1 of a 2-part publication we evaluate the incidence and predictors of RASP as well as determine whether any association exists between RASP and patient-reported outcomes (PROs). METHODS: Data were prospectively collected during a US Food and Drug Administration randomized, multicenter, investigational device exemption trial comparing CDA (Mobi-C; Zimmer Biomet, Westminster, CO) with ACDF. Multiple post hoc analyses were conducted on RASP as it related to demographics and patient outcomes. Kaplan-Meier estimates of time to Kellgren-Lawrence (K-L) grade 3/4 were calculated separately for all groups. Multivariate Cox proportional hazard models were used analyze whether RASP was associated with patient preoperative demographic characteristics and preoperative and postoperative radiographic characteristics. The association of RASP with PROs was analyzed using generalized estimating equations and matched, retrospective cohort analysis. RESULTS: The incidence of grade 3/4 RASP was lower for patients treated with CDA when initial treatment was at 1 level (27% vs 47%, P < .0001) and at 2 levels (14% vs 49%, P < .0001). Kaplan-Meier estimates indicated significantly lower probability of grade 3/4 RASP over time for patients receiving CDA (P < .001). Treatment with ACDF, treatment of 1 level, higher age, body mass index, higher preoperative physical components score, and a lower Cobb angle were associated with elevated risk of grade 3/4 RASP. CDA was shown to be more effective than ACDF (64.4%; 95% CI = 50.9, 74.2; P < .0001) at preventing RASP. CONCLUSIONS: The incidence and risk of RASP is decreased when patients are treated with CDA compared with ACDF. Although the mechanism of CDA that generates this protective effect is not understood, PROs remain unaffected through 7 years despite changes in RASP.

Adjacent Segment Pathology After Treatment With Cervical Disc Arthroplasty or Anterior Cervical Discectomy and Fusion, Part 2: Clinical Results at 7-Year Follow-Up.

BACKGROUND: Adjacent segment pathology (ASP) following cervical disc arthroplasty (CDA) or anterior cervical discectomy and fusion (ACDF) is identified by imaging (RASP) or clinical symptoms (CASP). Clinical symptoms of CASP have been broadly defined, but subsequent adjacent-level surgeries are clear indicators of CASP. Current literature remains inconsistent in the incidence and potential predictors of CASP. Here, we will evaluate a robust data set for the incidence of CASP resulting in subsequent surgery, attempt to identify factors that might affect CASP, and analyze the association of CASP with patient-reported outcomes (PROS) and RASP. METHODS: Data were prospectively collected during a US Food and Drug Administration randomized, multicenter, investigational device exemption trial comparing CDA (Mobi-C, Zimmer Biomet, Westminster, CO) with ACDF. CASP was defined as any adjacent-level subsequent surgical intervention. Post hoc analyses were conducted on the incidence, time to CASP diagnosis, and relationship of CASP with patient demographics. Longitudinal retrospective case-control analysis was used to assess the correlation of CASP to PROs and radiographic adjacent segment pathology (RASP). RESULTS: Kaplan-Meier estimates indicated significantly lower probability of CASP over time for 1-level (P = .002) and 2-level (P = .008) CDA patients. Treatment with ACDF and younger age were associated with higher CASP risk. CDA was more effective than ACDF (70.5%; 95% CI = 45.1, 84.2; P < .0001) at preventing CASP. Case-control analysis indicated increased probability of CASP for patients with grade 3/4 RASP, but the difference was not statistically significant. When we pooled CASP patients, the median grade of RASP at the visit prior to surgery was 1, with only 6 patients presenting with grade 3/4 RASP. CONCLUSIONS: Patients treated with CDA have a lower incidence of CASP than do patients treated with ACDF, although the mechanism remains unclear. CASP and RASP remain uncorrelated in this large data set, but other predictive variables such as treatment, age, and number of levels should be further investigated.

Sagittal Alignment of the Lumbar Spine.

Alignment of the lumbar spine has an important impact on the segmental motion, degenerative pathology, and health-related quality of life. The relationship between lumbar lordosis and pelvic incidence is predictive in the pathogenesis of spinal disorders, including disk degeneration, spondylolisthesis, and adjacent segment degeneration. This article reviews the relationship between lumbar and pelvic alignment with pathology of the lumbar spine, provides goals for appropriate alignment in reconstructive surgery, and discusses strategies for effective realignment of the spine.

Risk factors for 30-day reoperation and 3-month readmission: analysis from the Quality and Outcomes Database lumbar spine registry.

OBJECTIVE The aim of this paper was to use a prospective, longitudinal, multicenter outcome registry of patients undergoing surgery for lumbar degenerative disease in order to assess the incidence and factors associated with 30-day reoperation and 90-day readmission. METHODS Prospectively collected data from 9853 patients from the Quality and Outcomes Database (QOD; formerly known as the N2QOD [National Neurosurgery Quality and Outcomes Database]) lumbar spine registry were retrospectively analyzed. Multivariate binomial regression analysis was performed to identify factors associated with 30-day reoperation and 90-day readmission after surgery for lumbar degenerative disease. A subgroup analysis of Medicare patients stratified by age (< 65 and ≥ 65 years old) was also performed. Continuous variables were compared using unpaired t-tests, and proportions were compared using Fisher's exact test. RESULTS There was a 2% reoperation rate within 30 days. Multivariate analysis revealed prolonged operative time during the index case as the only independent factor associated with 30-day reoperation. Other factors such as preoperative diagnosis, body mass index (BMI), American Society of Anesthesiologists (ASA) class, diabetes, and use of spinal implants were not associated with reoperations within 30 days. Medicare patients < 65 years had a 30-day reoperation rate of 3.7%, whereas those ≥ 65 years had a 30-day reoperation rate of 2.2% (p = 0.026). Medicare beneficiaries younger than 65 years undergoing reoperation within 30 days were more likely to be women (p = 0.009), have a higher BMI (p = 0.008), and have higher rates of depression (p < 0.0001). The 90-day readmission rate was 6.3%. Multivariate analysis demonstrated that higher ASA class (OR 1.46 per class, 95% CI 1.25-1.70) and history of depression (OR 1.27, 95% CI 1.04-1.54) were factors associated with 90-day readmission. Medicare beneficiaries had a higher rate of 90-day readmissions compared with those who had private insurance (OR 1.43, 95% CI 1.17-1.76). Medicare patients < 65 years of age were more likely to be readmitted within 90 days after their index surgery compared with those ≥ 65 years (10.8% vs 7.7%, p = 0.017). Medicare patients < 65 years of age had a significantly higher BMI (p = 0.001) and higher rates of depression (p < 0.0001). CONCLUSIONS In this analysis of a large prospective, multicenter registry of patients undergoing lumbar degenerative surgery, multivariate analysis revealed that prolonged operative time was associated with 30-day reoperation. The authors found that factors associated with 90-day readmission included higher ASA class and a history of depression. The 90-day readmission rates were higher for Medicare beneficiaries than for those who had private insurance. Medicare patients < 65 years of age were more likely to undergo reoperation within 30 days and to be readmitted within 90 days after their index surgery.

Excision of Thoracic Chondrosarcoma: Case Report and Review of Literature.

Chondrosarcomas are cartilage-matrix-forming tumors that make up 20-27% of primary malignant bone tumors and are the third most common primary bone malignancy after multiple myelomas and osteosarcomas. Radiographic assessment of this condition includes plain radiography, computed tomography, and magnetic resonance imaging for tumor characterization and delineation of intraosseous and extraosseous involvement. Most chondrosarcomas are refractory to chemotherapy and radiation therapy; therefore, wide en bloc surgical excision offers the best chance for cure. Chondrosarcomas frequently affect the pelvis and upper and lower extremities. In rare instances, the chest wall can be involved, with chondrosarcomas occurring in the ribs, sternum, anterior costosternal junction, and posterior costotransverse junction. In this article, we present a patient with thoracic chondrosarcoma centered at the left T7 costotransverse joint with effacement of the left T7-T8 neuroforamen. We also detail our operative technique of wide en bloc chondrosarcoma excision and review current literature on this topic.

Anterior Transsternal Approach for Treatment of Upper Thoracic Vertebral Osteomyelitis: Case Report and Review of the Literature.

Direct ventral access to the cervicothoracic spine (C7-T4) poses a technical challenge in spine surgery, given the vital neurovascular structures residing anterior to the cervicothoracic junction (CTJ). The transsternal approach is a feasible surgical option that allows for direct anterior exposure of the lower cervical and upper thoracic vertebrae. Here, the authors report a case of an elderly gentleman with upper thoracic (T1-2) vertebral osteomyelitis and epidural abscess who underwent a transsternal full median sternotomy for ventral decompression and fusion of C7-T2. We also detail our operative procedure and review relevant literature on different transsternal approaches to the CTJ.

A controlled anterior sequential interbody dilation technique for correction of cervical kyphosis.

OBJECT: Cervical kyphosis can lead to spinal instability, spinal cord injury, and disability. The correction of cervical kyphosis is technically challenging, especially in severe cases. The authors describe the anterior sequential interbody dilation technique for the treatment of cervical kyphosis and evaluate perioperative outcomes, degree of correction, and long-term follow-up outcomes associated with the technique. METHODS: In the period from 2006 to 2011, a consecutive cohort of adults with cervical kyphosis (Cobb angles ≥ 0°) underwent sequential interbody dilation, a technique entailing incrementally increased interbody distraction with the sequential placement of larger spacers (at least 1 mm) in the discectomy and/or corpectomy spaces. The authors retrospectively reviewed these patients, and primary outcomes of interest included kyphosis correction, blood loss, hospital stay, complications, Nurick grade, pain, reoperation, and pseudarthrosis. A subgroup analysis among patients with preoperative kyphosis of 0°-9° (mild), 10°-19° (moderate), and ≥ 20° (severe) was performed. RESULTS: One hundred patients were included in the study: 74 with mild preoperative cervical kyphosis, 19 with moderate, and 7 with severe. The mean patient age was 53.1 years, and 54.0% of the patients were male. Mean estimated blood loss was 305.6 ml, and the mean length of hospital stay was 5.2 days. The overall complication rate was 9.0%, and there were no deaths. Sixteen percent of patients underwent supplemental posterior fusion. There was significant correction in cervical alignment (p < 0.001), and the mean overall kyphosis correction was 12.4°. Patients with severe preoperative kyphosis gained a correction of 24.7°, those with moderate kyphosis gained 17.8°, and those with mild kyphosis gained 10.1°. A mean correction of 32.0° was obtained if 5 levels were addressed. The mean follow-up was 26.8 months. The reoperation rate was 4.7%. At follow-up, there was significant improvement in visual analog scale neck pain (p = 0.020) and Nurick grade (p = 0.037). The pseudarthrosis rate was 6.3%. CONCLUSIONS: Sequential interbody dilation is a feasible and effective method of correcting cervical kyphosis. Complications and reoperation rates are low. Similar benefits are seen among all severities of kyphosis, and greater correction can be achieved in more severe cases.

Adjustment of suboptimally placed lumbar pedicle screws decreases pullout strength and alters biomechanics of the construct: a pilot cadaveric study.

BACKGROUND: Lumbar pedicle screws are placed for internal fixation and help to enhance bony fusion. Optimal screws are medially directed, should be parallel or pointing to the superior endplate, and penetrate 50%-80% of the vertebral body. "Nonparallel" pedicle screws can be inadvertently placed within the confines of the pedicle and vertebral body but are sometimes replaced to obtain a more acceptable postoperative image. A nonparallel (suboptimal) screw is one that is located within the pedicle and body and does not violate bone; however, it is not parallel to the superior endplate. These "cored-out" grooves left in the bone from the initial tap and screw placement may compromise the integrity of the bone and the construct. METHODS: Dual-energy x-ray absorptiometry scans and L4-5 laminectomies were performed on 6 fresh-frozen cadaveric lumbar spines. We placed 2 optimal pedicle screws in L4, 1 optimal screw in L5, and 1 suboptimal screw in L5 (construct A). Axial rotation, flexion/extension, and lateral bending were tested. The suboptimal screw was repositioned in an optimal trajectory and retested (construct B). Pullout strength was performed on optimal and revised L5 pedicle screws. RESULTS: The mean axial rotation stiffness was 1.31 N-m/degrees ± 0.22 in construct A and 1.19 N-m/degrees ± 0.17 in construct B (P = 0.023; 95% CI [CI], 0.20-0.02). The mean lateral bending stiffness was 0.015 N/mm ± 0.002 in construct A and 0.016 N/mm ± 0.002 in construct B (P = 0.3; 95% CI, 0.0008-0.001). The mean flexion/extension stiffness was 0.0139 N/mm ± 0.002 in construct A and 0.0126 N/mm ± 0.002 in construct B (P = 0.01; 95% CI, 0.002-0.0004). Axial rotation and flexion/extension stiffness were significantly different between the 2 groups. The mean pullout strength was significantly higher in the nonrevised parallel screw group compared with the reimplanted parallel screw group (906.93 N ± 271.17 vs. 608.32 N ± 207.23, P = 0.031). Dual-energy x-ray absorptiometry imaging demonstrated 4 osteopenic and 2 osteoporotic specimens, although differences in bone mineral density did not play a significant role in assessing either the biomechanical parameters or the pullout strength. CONCLUSIONS: Great care is warranted in the initial placement of lumbar pedicle screws. Revising a nonparallel screw placement decreases pullout strength and alters biomechanical movements (axial rotation and flexion/extension) in patients with decreased bone mineral density. If a screw is inadvertently placed nonparallel to the endplate but is within the confines of the pedicle and vertebral body with adequate bone purchase, it should not be revised and rather be left in its place.

Perioperative morbidity and mortality comparison in circumferential cervical fusion for osteomyelitis versus cervical spondylotic myelopathy.

OBJECT: The most common indications for circumferential cervical decompression and fusion are cervical spondylotic myelopathy (CSM) and cervical osteomyelitis (COM). Currently, the informed consent process prior to circumferential cervical fusion surgery is not different for these two groups of patients, as details of their diagnosis-specific risk profiles have not been quantified. The authors compared two patient cohorts with either CSM or COM treated using circumferential fusion. They sought to quantify perioperative morbidity and postoperative mortality in these two groups to assist with a diagnosis-specific informed consent process for future patients undergoing this type of surgery. METHODS: Perioperative and follow-up data from two cohorts of patients who had undergone circumferential cervical decompression and fusion were analyzed. Estimated blood loss (EBL), length of stay (LOS), perioperative complications, hospital readmission, 30-day reoperation rates, change in Nurick grade, and mortality were compared between the two groups. RESULTS: Twenty-two patients were in the COM cohort, and 24 were in the CSM cohort. Complications, hospital readmission, 30-day reoperation rates, EBL, and mortality were not statistically different, although patients with COM trended higher in each of these categories. There was a significantly greater LOS (p < 0.001) in the COM group and greater improvement in Nurick grade in the CSM group (p < 0.001). CONCLUSIONS: When advising patients undergoing circumferential fusion about perioperative risk factors, it is important for those with COM to know that they are likely to have a higher rate of complications and mortality than those with CSM who are undergoing similar surgery. Furthermore, COM patients have less neurological improvement than CSM patients after surgery. This information may be useful to surgeons and patients in providing appropriate informed consent during preoperative planning.

Traumatic thoracolumbar spinal injury: an algorithm for minimally invasive surgical management.

OBJECT: Minimally invasive spinal (MIS) surgery techniques have been used sporadically in thoracolumbar junction trauma cases in the past 5 years. A review of the literature on the treatment of thoracolumbar trauma treated with MIS surgery revealed no unifying algorithm to assist with treatment planning. Therefore, the authors formulated a treatment algorithm. METHODS: The authors reviewed the current literature on MIS treatment of thoracolumbar trauma. Based on the literature review, they then created an algorithm for the treatment of thoracolumbar trauma utilizing MIS techniques. This MIS trauma treatment algorithm incorporates concepts form the Thoracolumbar Injury Classification System (TLICS). RESULTS: The authors provide representative cases of patients with thoracolumbar trauma who underwent MIS surgery utilizing the MIS trauma treatment algorithm. The cases involve the use of mini-open lateral approaches and/or minimally invasive posterior decompression with or without fusion. CONCLUSIONS: Cases involving thoracolumbar trauma can safely be treated with MIS surgery in select cases of burst fractures. The role of percutaneous nonfusion techniques remains very limited (primarily to treat thoracolumbar trauma in patients with a propensity for autofusion [for example, those with ankylosing spondylitis]).

Bihemispheric posterior inferior cerebellar artery occurring with an azygos anterior cerebral artery: case study.

Variations in intracranial vasculature are well known. We report a rare anatomic variation in a patient who underwent cerebral angiography for suspected intracranial aneurysm. Digital subtraction angiography revealed a bihemispheric posterior inferior cerebellar artery (PICA) and an azygous anterior cerebral artery (ACA). There was no evidence of any aneurysm or vascular abnormality. To our knowledge, this is the first reported case of a patient with a common PICA supplying both the cerebellar hemispheres and a common ACA supplying ACA territory bilaterally. It is important for the physician to be aware of these anatomical variations in order to differentiate a normal variant from a pathological condition.

Cost-effectiveness of lumbar discectomy and single-level fusion for spondylolisthesis: experience with the NeuroPoint-SD registry.

OBJECT: There is significant practice variation and uncertainty as to the value of surgical treatments for lumbar spine disorders. The authors' aim was to establish a multicenter registry to assess the efficacy and costs of common lumbar spinal procedures by using prospectively collected outcomes. METHODS: An observational prospective cohort study was completed at 13 academic and community sites. Patients undergoing single-level fusion for spondylolisthesis or single-level lumbar discectomy were included. The 36-Item Short Form Health Survey (SF-36) and Oswestry Disability Index (ODI) data were obtained preoperatively and at 1, 3, 6, and 12 months postoperatively. Power analysis estimated a sample size of 160 patients: lumbar disc (125 patients) and lumbar listhesis (35 patients). The quality-adjusted life year (QALY) data were calculated using 6-dimension utility index scores. Direct costs and complication costs were estimated using Medicare reimbursement values from 2011, and indirect costs were estimated using the human capital approach with the 2011 US national wage index. Total costs equaled $14,980 for lumbar discectomy and $43,852 for surgery for lumbar spondylolisthesis. RESULTS: There were 198 patients enrolled over 1 year. The mean age was 46 years (49% female) for lumbar discectomy (n = 148) and 58.1 years (60% female) for lumbar spondylolisthesis (n = 50). Ten patients with disc herniation (6.8%) and 1 with listhesis (2%) required repeat operation at 1 year. The overall 1-year follow-up rate was 88%. At 30 days, both lumbar discectomy and single-level fusion procedures were associated with significant improvements in ODI, visual analog scale, and SF-36 scores (p = 0.0002), which persisted at the 1-year evaluation (p < 0.0001). By 1 year, more than 80% of patients in each cohort who were working preoperatively had returned to work. Lumbar discectomy was associated with a gain of 0.225 QALYs over the 1-year study period ($66,578/QALY gained). Lumbar spinal fusion for Grade I listhesis was associated with a gain of 0.195 QALYs over the 1-year study period ($224,420/QALY gained). CONCLUSIONS: This national spine registry demonstrated successful collection of high-quality outcomes data for spinal procedures in actual practice. These data are useful for demonstrating return to work and cost-effectiveness following surgical treatment of single-level lumbar disc herniation or spondylolisthesis. One-year cost per QALY was obtained, and this cost per QALY is expected to improve further by 2 years. This work sets the stage for real-world analysis of the value of health interventions.

Unilateral versus bilateral iliac screws for spinopelvic fixation: are two screws better than one?

OBJECT: Long-segment spinal instrumentation ending at the sacrum places substantial biomechanical stress on sacral screws. Iliac (pelvic) screws relieve some of this stress by supplementing the caudal fixation. It remains an open question whether there is any clinically significant difference in sacropelvic fixation with bilateral versus unilateral iliac screws. The primary purpose of this study was to compare clinical and radiographic complications in the use of bilateral versus unilateral iliac screw fixation. METHODS: The authors retrospectively reviewed 102 consecutive spinal fixation cases that extended to the pelvis at a single institution (University of California, San Francisco) in the period from 2005 to 2012 performed by the senior authors. Charts were reviewed for the following complications: reoperation, L5-S1 pseudarthrosis, sacral insufficiency fracture, hardware prominence, iliac screw loosening, and infection. The t-test, Pearson chi-square test, and Fisher exact test were used to determine statistical significance. RESULTS: The mean follow-up was 31 months. Thirty cases were excluded: 12 for inadequate follow-up, 15 for lack of L5-S1 interbody fusion, and 3 for preoperative osteomyelitis. The mean age among the 72 remaining cases was 62 years (range 39-79 years). Forty-six patients underwent unilateral and 26 bilateral iliac screw fixation. Forty-one percent (n = 19) of the unilateral cases and 50% (n = 13) of the bilateral cases were treated with reoperation (p = 0.48). In addition, 13% (n = 6) of the unilateral and 19% (n = 5) of the bilateral cases developed L5-S1 pseudarthrosis (p = 0.51). There were no sacral insufficiency fractures. Thirteen percent (n = 6) of the unilateral and 7.7% (n = 2) of the bilateral cases developed postoperative infection (p = 0.70). CONCLUSIONS: In a retrospective single-institution study, single versus dual pelvic screws led to comparable rates of reoperation, iliac screw removal, postoperative infection, pseudarthrosis, and sacral insufficiency fractures. For spinopelvic fixation, placing bilateral (vs unilateral) pelvic screws produced no added clinical benefit in most cases.

Minimally invasive extracavitary transpedicular corpectomy for the management of spinal tumors.

Management of spinal metastasis is a large and challenging clinical problem. For metastatic epidural spinal cord compression, a prospective, randomized, controlled trial showed the utility of circumferential surgical decompression followed by adjuvant radiotherapy. In the setting of those data, surgical techniques evolved from decompressive laminectomy only to anterior corpectomy to posterior-only transpedicular corpectomy. The transpedicular approach has recently been modernized with minimally invasive and mini-open techniques. This article presents the relevant clinical background on spinal metastasis, reviews the surgical technique for minimally invasive transpedicular corpectomy, and finally reviews relevant results in the literature.

Comparison between C1-2 Fixation with and without Supplemental Posterior Wiring.

Study Design Retrospective analysis. Clinical Question Is there a difference between the screw-rod construct (SRC) procedure without wiring and the SRC procedure with wiring with respect to fusion, implant failure, reoperation, donor-site morbidity, and complication rates? Patients and Methods We performed a retrospective analysis of 26 patients who underwent C1-2 fixation between 2004 and 2012 (SRC with wiring and structural bone graft, 13 patients; SRC with autograft but without wiring, 13 patients). Fusion was assessed using dynamic X-rays in all patients and computed tomographic scans in selected cases. Pseudoarthrosis was confirmed during reoperation. Results The mean follow-up time was 2 years and 5 months for the SRC without wiring group and 2 years and 1 month for the SRC with wiring group. Patients with less than 1-year follow-up time were excluded. The fusion rate, implant failure rate, and reoperation rates for the SRC without wiring group were 92, 8, and 8%, respectively. The fusion, implant failure, and reoperation rates for the SRC with wiring group were 100, 0, and 0%, respectively. There were no donor-site morbidities or complications in either group (both 0%). There were no differences in parameters we examined between the two groups (p > 0.05 for each rate, Fisher exact test). Conclusions The results suggest that supplementing the SRC procedure with wiring may increase fusion rate, but this difference is not statistically significant. Although the sample size was small, there was not a significant discrepancy in outcomes between the two groups at an average follow-up of 2 years. [Table: see text].

Dysphagia following posterior fossa surgery in adults.

OBJECTIVE: Our study seeks to assess the incidence of aspiration and prolonged dysphagia needing enteral feeding at discharge (EFD) in adults after posterior fossa (p-fossa) surgery. METHODS: A retrospective review was done on 56 patients with p-fossa surgery who needed a swallowing evaluation postoperatively. Questionnaires were sent to patients with EFD. Using univariate and multiple logistic regression analysis, risk factors for aspiration, EFD, and continued enteral feeds were identified. RESULTS: Most patients were male and had p-fossa tumors. Multiple swallowing evaluations were needed in 25 (45%) patients. Aspiration was seen in 23 (41%) and 16 (27%) had EFD. Older age and number of evaluations were significantly associated with both aspiration and EFD (P < 0.05). Lateral approach was significantly associated with EFD (P = 0.047). In addition, multiple logistic regression identified aspiration as an independent significant predictor for EFD (P < 0.01). Mean operative time and tumor location did not have a significant correlation with EFD. At mean follow-up (15 months), only 5/16 needed continued enteral feeds. CONCLUSION: Although 27% patients had EFD after p-fossa surgery, only 5/56 (9%) required continued enteral feeding. Aspiration, age, and lateral surgical approach is associated with EFD. In patients who demonstrate aspiration, we recommend placement of enteral feeding tube. Although most will not require continued enteral feeding at follow-up, longer follow-ups are needed.