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Michael M. Safaee, Cecilia L. Dalle Ore, Corinna C. Zygourakis, Vedat Deviren and Christopher P. Ames

OBJECTIVE

Proximal junctional kyphosis (PJK) is a well-recognized complication of surgery for adult spinal deformity and is characterized by increased kyphosis at the upper instrumented vertebra (UIV). PJK prevention strategies have the potential to decrease morbidity and cost by reducing rates of proximal junctional failure (PJF), which the authors define as radiographic PJK plus clinical sequelae requiring revision surgery.

METHODS

The authors performed an analysis of 195 consecutive patients with adult spinal deformity. Age, sex, levels fused, upper instrumented vertebra (UIV), use of 3-column osteotomy, pelvic fixation, and mean time to follow-up were collected. The authors also reviewed operative reports to assess for the use of surgical adjuncts targeted toward PJK prevention, including ligament augmentation, hook fixation, and vertebroplasty. The cost of surgery, including direct and total costs, was also assessed at index surgery and revision surgery. Only revision surgery for PJF was included.

RESULTS

The mean age of the cohort was 64 years (range 25–84 years); 135 (69%) patients were female. The mean number of levels fused was 10 (range 2–18) with the UIV as follows: 2 cervical (1%), 73 upper thoracic (37%), 108 lower thoracic (55%), and 12 lumbar (6%). Ligament augmentation was used in 99 cases (51%), hook fixation in 60 cases (31%), and vertebroplasty in 71 cases (36%). PJF occurred in 18 cases (9%). Univariate analysis found that ligament augmentation and hook fixation were associated with decreased rates of PJF. However, in a multivariate model that also incorporated age, sex, and UIV, only ligament augmentation maintained a significant association with PJF reduction (OR 0.196, 95% CI 0.050–0.774; p = 0.020). Patients with ligament augmentation, compared with those without, had a higher cost of index surgery, but ligament augmentation was overall cost effective and produced significant cost savings. In sensitivity analyses in which we independently varied the reduction in PJF, cost of ligament augmentation, and cost of reoperation by ± 50%, ligament augmentation remained a cost-effective strategy for PJF prevention.

CONCLUSIONS

Prevention strategies for PJK/PJF are limited, and their cost-effectiveness has yet to be established. The authors present the results of 195 patients with adult spinal deformity and show that ligament augmentation is associated with significant reductions in PJF in both univariate and multivariate analyses, and that this intervention is cost-effective. Future studies will need to determine if these clinical results are reproducible, but for high-risk cases, these data suggest an important role of ligament augmentation for PJF prevention and cost savings.

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Michael Safaee, Andrew T. Parsa, Nicholas M. Barbaro, Dean Chou, Praveen V. Mummaneni, Philip R. Weinstein, Tarik Tihan and Christopher P. Ames

OBJECT

Intradural extramedullary spine tumors represent two-thirds of all primary spine neoplasms. Approximately half of these are peripheral nerve sheath tumors, mainly neurofibromas and schwannomas. Given the rarity of this disease and, thus, the limited analyses of clinical outcomes, the authors examined the association of tumor location, extent of resection, and neurofibromatosis (NF) status with clinical outcomes.

METHODS

Patients were identified through a search of the University of California, San Francisco, neuropathology database and a separate review of current procedural terminology codes. Data recorded included patient age, patient sex, clinical presentation, presence of NF, tumor type, tumor location, extent of resection (gross-total resection [GTR] or subtotal resection [STR]), and clinical follow-up.

RESULTS

Of 221 tumors in 199 patients (mean age 45 years), 53 were neurofibromas, 163 were schwannomas, and 5 were malignant peripheral nerve sheath tumors. The most common presenting symptom was spinal pain (76%), followed by weakness (36%) and sensory abnormalities (34%). Mean symptom duration was 16 months. In terms of spinal location, neurofibromas were more common in the cervical spine (74% vs 27%, p < 0.001), and schwannomas were more common in the thoracic and lumbosacral spine (73% vs 26%, p < 0.001). Rates of GTR were lower for neurofibromas than schwannomas (51% vs 83%, p < 0.001), regardless of location. Rates of GTR were lower for cervical (54%) than thoracic (90%) and lumbosacral (86%) lesions (p < 0.001). NF was associated with lower rates of GTR among all tumors (43% vs 86%, p < 0.001). The mean follow-up time was 32 months. Recurrence/progression was more common for neurofibromas than schwannomas (17% vs 7%, p = 0.03), although the mean time to recurrence/progression did not differ according to tumor type (45 vs 53 months, p = 0.63). As expected, GTR was associated with lower recurrence rates (4% vs 22%, p < 0.001). According to multivariate analysis, cervical location (OR 0.239, 95% CI 0.110–0.520) and presence of NF (OR 0.166, 95% CI 0.054–0.507) were associated with lower rates of GTR. In a separate model, only GTR (OR 0.141, 95% CI 0.046–0.429) was associated with tumor recurrence.

CONCLUSIONS

Resection is an effective treatment for spinal nerve sheath tumors. Neurofibromas were found more commonly in the cervical spine than in other regions of the spine and were associated with higher rates of recurrence and lower rates of GTR than other tumor types, particularly in patients with NF Types 1 or 2. According to multivariate analysis, both cervical location and presence of NF were associated with lower rates of GTR. According to a second multivariate model, the only variable associated with tumor recurrence was extent of resection. Maximal safe resection remains ideal for these lesions; however, patients with cervical tumors or NF should be counseled about their increased risk for recurrence.

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Michael P. Kelly, Lawrence G. Lenke, Christopher I. Shaffrey, Christopher P. Ames, Leah Y. Carreon, Virginie Lafage, Justin S. Smith and Adam L. Shimer

Object

The goal in this study was to evaluate the risk factors for complications, including new neurological deficits, in the largest cohort of patients with adult spinal deformity to date.

Methods

The Scoli-RISK-1 inclusion criteria were used to identify eligible patients from 5 centers who were treated between June 1, 2009, and June 1, 2011. Records were reviewed for patient demographic information, surgical data, and reports of perioperative complications. Neurological deficits were recorded as preexisting or as new deficits. Patients who underwent 3-column osteotomies (3COs) were compared with those who did not (posterior spinal fusion [PSF]). Between-group comparisons were performed using independent samples t-tests and chi-square analyses.

Results

Two hundred seven patients were identified—75 who underwent PSF and 132 treated with 3CO. In the latter group, patients were older (58.9 vs 49.4 years, p < 0.001), had a higher body mass index (29.0 vs 25.8, p = 0.029), smaller preoperative coronal Cobb measurements (33.8° vs 56.4°, p < 0.001), more preoperative sagittal malalignment (11.7 cm vs 5.4 cm, p < 0.001), and similar sagittal Cobb measurements (45.8° vs 57.7°, p = 0.113). Operating times were similar (393 vs 423 minutes, p = 0.130), although patients in the 3CO group sustained higher estimated blood loss (2120 vs 1700 ml, p = 0.066). Rates of new neurological deficits were similar (PSF: 6.7% vs 3CO: 9.9%, p = 0.389), and rates of any perioperative medical complication were similar (PSF: 46.7% vs 3CO: 50.8%, p = 0.571). Patients who underwent vertebral column resection (VCR) were more likely to sustain medical complications than those treated with pedicle subtraction osteotomy (73.7% vs 46.9%, p = 0.031), although new neurological deficits were similar (15.8% vs 8.8%, p = 0.348). Regression analysis did not reveal significant predictors of neurological injury or complication from collected data.

Conclusions

Despite higher estimated blood loss, rates of all complications (49.3%) and new neurological deficits (8.7%) did not vary for patients who underwent complex reconstruction, whether or not a 3CO was performed. Patients who underwent VCR sustained more medical complications without an increase in new neurological deficits. Prospective studies of patient factors, provider factors, and refined surgical data are needed to define and optimize risk factors for complication and neurological deficits.

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Aaron J. Clark, John E. Ziewacz, Michael Safaee, Darryl Lau, Russ Lyon, Dean Chou, Philip R. Weinstein, Christopher P. Ames, John P. Clark III and Praveen V. Mummaneni

Object

The use of intraoperative neurophysiological monitoring (IONM) in surgical decompression surgery for myelopathy may assist the surgeon in taking corrective measures to reduce or prevent permanent neurological deficits. We evaluated the efficacy of IONM in cervical and cervicothoracic spondylotic myelopathy (CSM) cases.

Methods

The authors retrospectively reviewed 140 cases involving patients who underwent surgery for CSM utilizing IONM during 2011 at the University of California, San Francisco. Data on preoperative clinical variables, intraoperative changes in transcranial motor evoked potentials (MEPs), and postoperative new neurological deficits were collected. Associations between categorical variables were analyzed with the Fisher exact test.

Results

Of the 140 patients, 16 (11%) had significant intraoperative decreases in MEPs. In 8 of these cases, the MEP signal did not return to baseline values by the end of the operation. There were 8 (6%) postoperative deficits, of which 6 were C-5 palsies and 2 were paraparesis. Six of the patients with postoperative deficits had demonstrated persistent MEP signal change on IONM. There was a significant association between persistent MEP changes and postoperative deficits (p < 0.001). The sensitivity of intraoperative MEP monitoring was 75%, the specificity 98%, the positive predictive value 75%, and the negative predictive value 98%. Due to higher rates of false negatives, the sensitivity decreased to 60% in the subgroup of patients with vascular disease comorbidity. The sensitivity increased to 100% in elderly patients and in patients with preoperative motor deficits. The sensitivity and positive predictive value of deltoid and biceps MEP changes in predicting C-5 palsy were 67% and 67%, respectively.

Conclusions

The authors found a correlation between decreased intraoperative MEPs and postoperative new neurological deficits in patients with CSM. Sensitivity varies based on patient comorbidities, age, and preoperative neurological function. Monitoring of MEPs is a useful adjunct for CSM cases, and the authors have developed a checklist to standardize their responses to intraoperative MEP changes.

Free access

Carolyn J. Sparrey, Jeannie F. Bailey, Michael Safaee, Aaron J. Clark, Virginie Lafage, Frank Schwab, Justin S. Smith and Christopher P. Ames

The goal of this review is to discuss the mechanisms of postural degeneration, particularly the loss of lumbar lordosis commonly observed in the elderly in the context of evolution, mechanical, and biological studies of the human spine and to synthesize recent research findings to clinical management of postural malalignment. Lumbar lordosis is unique to the human spine and is necessary to facilitate our upright posture. However, decreased lumbar lordosis and increased thoracic kyphosis are hallmarks of an aging human spinal column. The unique upright posture and lordotic lumbar curvature of the human spine suggest that an understanding of the evolution of the human spinal column, and the unique anatomical features that support lumbar lordosis may provide insight into spine health and degeneration. Considering evolution of the skeleton in isolation from other scientific studies provides a limited picture for clinicians. The evolution and development of human lumbar lordosis highlight the interdependence of pelvic structure and lumbar lordosis. Studies of fossils of human lineage demonstrate a convergence on the degree of lumbar lordosis and the number of lumbar vertebrae in modern Homo sapiens. Evolution and spine mechanics research show that lumbar lordosis is dictated by pelvic incidence, spinal musculature, vertebral wedging, and disc health. The evolution, mechanics, and biology research all point to the importance of spinal posture and flexibility in supporting optimal health. However, surgical management of postural deformity has focused on restoring posture at the expense of flexibility. It is possible that the need for complex and costly spinal fixation can be eliminated by developing tools for early identification of patients at risk for postural deformities through patient history (genetics, mechanics, and environmental exposure) and tracking postural changes over time.

Free access

David B. Bumpass, Lawrence G. Lenke, Jeffrey L. Gum, Christopher I. Shaffrey, Justin S. Smith, Christopher P. Ames, Shay Bess, Brian J. Neuman, Eric Klineberg, Gregory M. Mundis Jr., Frank Schwab, Virginie Lafage, Han Jo Kim, Douglas C. Burton, Khaled M. Kebaish, Richard Hostin, Renaud Lafage, Michael P. Kelly and for the International Spine Study Group

OBJECTIVE

Adolescent spine deformity studies have shown that male patients require longer surgery and have greater estimated blood loss (EBL) and complications compared with female patients. No studies exist to support this relationship in adult spinal deformity (ASD). The purpose of this study was to investigate associations between sex and complications, deformity correction, and health-related quality of life (HRQOL) in patients with ASD. It was hypothesized that male ASD patients would have greater EBL, longer surgery, and more complications than female ASD patients.

METHODS

A multicenter ASD cohort was retrospectively queried for patients who underwent primary posterior-only instrumented fusions with a minimum of 5 levels fused. The minimum follow-up was 2 years. Primary outcomes were EBL, operative time, intra-, peri-, and postoperative complications, radiographic correction, and HRQOL outcomes (Oswestry Disability Index, SF-36, and Scoliosis Research Society-22r Questionnaire). Poisson multivariate regression was used to control for age, comorbidities, and levels fused.

RESULTS

Ninety male and 319 female patients met the inclusion criteria. Male patients had significantly greater mean EBL (2373 ml vs 1829 ml, p = 0.01). The mean operative time, transfusion requirements, and final radiographic measurements did not differ between sexes. Similarly, changes in HRQOL showed no significant differences. Finally, there were no sex differences in the incidence of complications (total, major, or minor) at any time point after controlling for age, body mass index, comorbidities, and levels fused.

CONCLUSIONS

Despite higher EBL, male ASD patients did not experience more complications or require less deformity correction at the 2-year follow-up. HRQOL scores similarly showed no sex differences. These findings differ from adolescent deformity studies, and surgeons can counsel patients that sex is unlikely to influence the outcomes and complication rates of primary all-posterior ASD surgery.

Free access

Gregory W. Poorman, Peter G. Passias, Samantha R. Horn, Nicholas J. Frangella, Alan H. Daniels, D. Kojo Hamilton, Hanjo Kim, Daniel Sciubba, Bassel G. Diebo, Cole A. Bortz, Frank A. Segreto, Michael P. Kelly, Justin S. Smith, Brian J. Neuman, Christopher I. Shaffrey, Virginie LaFage, Renaud LaFage, Christopher P. Ames, Robert Hart, Gregory M. Mundis Jr. and Robert Eastlack

OBJECTIVE

Depression and anxiety have been demonstrated to have negative impacts on outcomes after spine surgery. In patients with cervical deformity (CD), the psychological and physiological burdens of the disease may overlap without clear boundaries. While surgery has a proven record of bringing about significant pain relief and decreased disability, the impact of depression and anxiety on recovery from cervical deformity corrective surgery has not been previously reported on in the literature. The purpose of the present study was to determine the effect of depression and anxiety on patients’ recovery from and improvement after CD surgery.

METHODS

The authors conducted a retrospective review of a prospective, multicenter CD database. Patients with a history of clinical depression, in addition to those with current self-reported anxiety or depression, were defined as depressed (D group). The D group was compared with nondepressed patients (ND group) with a similar baseline deformity determined by propensity score matching of the cervical sagittal vertical axis (cSVA). Baseline demographic, comorbidity, clinical, and radiographic data were compared among patients using t-tests. Improvement of symptoms was recorded at 3 months, 6 months, and 1 year postoperatively. All health-related quality of life (HRQOL) scores collected at these follow-up time points were compared using t-tests.

RESULTS

Sixty-six patients were matched for baseline radiographic parameters: 33 with a history of depression and/or current depression, and 33 without. Depressed patients had similar age, sex, race, and radiographic alignment: cSVA, T-1 slope minus C2–7 lordosis, SVA, and T-1 pelvic angle (p > 0.05). Compared with nondepressed individuals, depressed patients had a higher incidence of osteoporosis (21.2% vs 3.2%, p = 0.028), rheumatoid arthritis (18.2% vs 3.2%, p = 0.012), and connective tissue disorders (18.2% vs 3.2%, p = 0.012). At baseline, the D group had greater neck pain (7.9 of 10 vs 6.6 on a Numeric Rating Scale [NRS], p = 0.015), lower mean EQ-5D scores (68.9 vs 74.7, p < 0.001), but similar Neck Disability Index (NDI) scores (57.5 vs 49.9, p = 0.063) and myelopathy scores (13.4 vs 13.9, p = 0.546). Surgeries performed in either group were similar in terms of number of levels fused, osteotomies performed, and correction achieved (baseline to 3-month measurements) (p < 0.05). At 3 months, EQ-5D scores remained lower in the D group (74.0 vs 78.2, p = 0.044), and NDI scores were similar (48.5 vs 39.0, p = 0.053). However, neck pain improved in the D group (NRS score of 5.0 vs 4.3, p = 0.331), and modified Japanese Orthopaedic Association (mJOA) scores remained similar (14.2 vs 15.0, p = 0.211). At 6 months and 1 year, all HRQOL scores were similar between the 2 cohorts. One-year measurements were as follows: NDI 39.7 vs 40.7 (p = 0.878), NRS neck pain score of 4.1 vs 5.0 (p = 0.326), EQ-5D score of 77.1 vs 78.2 (p = 0.646), and mJOA score of 14.0 vs 14.2 (p = 0.835). Anxiety/depression levels reported on the EQ-5D scale were significantly higher in the depressed cohort at baseline, 3 months, and 6 months (all p < 0.05), but were similar between groups at 1 year postoperatively (1.72 vs 1.53, p = 0.416).

CONCLUSIONS

Clinical depression was observed in many of the study patients with CD. After matching for baseline deformity, depression symptomology resulted in worse baseline EQ-5D and pain scores. Despite these baseline differences, both cohorts achieved similar results in all HRQOL assessments 6 months and 1 year postoperatively, demonstrating no clinical impact of depression on recovery up until 1 year after CD surgery. Thus, a history of depression does not appear to have an impact on recovery from CD surgery.