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Davis R.J.,Greater Baltimore Neurosurgical Inc. | Kim K.D.,University of California at Davis | Hisey M.S.,The Texas Institute | Hoffman G.A.,Orthopaedics Northeast | And 6 more authors.
Journal of Neurosurgery: Spine | Year: 2013

Object. Cervical total disc replacement (TDR) is intended to treat neurological symptoms and neck pain associated with degeneration of intervertebral discs in the cervical spine. Anterior cervical discectomy and fusion (ACDF) has been the standard treatment for these indications since the procedure was first developed in the 1950s. While TDR has been shown to be a safe and effective alternative to ACDF for treatment of patients with degenerative disc disease (DDD) at a single level of the cervical spine, few studies have focused on the safety and efficacy of TDR for treatment of 2 levels of the cervical spine. The primary objective of this study was to rigorously compare the Mobi-C cervical artificial disc to ACDF for treatment of cervical DDD at 2 contiguous levels of the cervical spine. Methods. This study was a prospective, randomized, US FDA investigational device exemption pivotal trial of the Mobi- C cervical artificial disc conducted at 24 centers in the US. The primary clinical outcome was a composite measure of study success at 24 months. The comparative control treatment was ACDF using allograft bone and an anterior plate. A total of 330 patients were enrolled, randomized, and received study surgery. All patients were diagnosed with intractable symptomatic cervical DDD at 2 contiguous levels of the cervical spine between C-3 and C-7. Patients were randomized in a 2:1 ratio (TDR patients to ACDF patients). Results. A total of 225 patients received the Mobi-C TDR device and 105 patients received ACDF. At 24 months only 3.0% of patients were lost to follow-up. On average, patients in both groups showed significant improvements in Neck Disability Index (NDI) score, visual analog scale (VAS) neck pain score, and VAS arm pain score from preoperative baseline to each time point. However, the TDR patients experienced significantly greater improvement than ACDF patients in NDI score at all time points and significantly greater improvement in VAS neck pain score at 6 weeks, and at 3, 6, and 12 months postoperatively. On average, patients in the TDR group also maintained preoperative segmental range of motion at both treated segments immediately postoperatively and throughout the study period of 24 months. The reoperation rate was significantly higher in the ACDF group at 11.4% compared with 3.1% for the TDR group. Furthermore, at 24 months TDR demonstrated statistical superiority over ACDF based on overall study success rates. Conclusions. The results of this study represent the first available Level I clinical evidence in support of cervical arthroplasty at 2 contiguous levels of the cervical spine using the Mobi-C cervical artificial disc. These results continue to support the use of cervical arthroplasty in general, but specifically demonstrate the advantages of 2-level arthroplasty over 2-level ACDF. Clinical trial registration no.: NCT00389597 (ClinicalTrials.gov). © Copyright 1944-2013 American Association of Neurological Surgeons.

Moller D.J.,University of California at Davis | Slimack N.P.,Northwestern University | Acosta F.L.,Cedars Sinai Spine Center | Koski T.R.,Northwestern University | And 2 more authors.
Neurosurgical Focus | Year: 2011

Object: Recently, the minimally invasive, lateral retroperitoneal, transpsoas approach to the thoracolumbar spinal column has been described by various authors. This is known as the minimally invasive lateral lumbar interbody fusion. The purpose of this study is to elucidate the approach-related morbidity associated with the minimally invasive transpsoas approach to the lumbar spine. To date, there have been only a couple of reports regarding the morbidity of the transpsoas muscle approach. Methods: A nonrandomized, prospective study utilizing a self-reported patient questionnaire was conducted between January 2006 and June 2008 at Northwestern University. Data were collected in 53 patients with a follow-up period ranging from 6 months to 3.5 years. Only 2 patients were lost to follow-up. Results: Thirty-six percent (19 of 53) of patients reported subjective hip flexor weakness, 25% (13 of 53) anterior thigh numbness, and 23% (12 of 53) anterior thigh pain. However, 84% of the 19 patients reported complete resolution of their subjective hip flexor weakness by 6 months, and most experienced improved strength by 8 weeks. Of those reporting anterior thigh numbness and pain, 69% and 75% improved to their baseline function by the 6-month follow-up evaluations, respectively. All patients with self-reported subjective hip flexor weakness underwent examinations during subsequent clinic visits after surgery; however, these examinations did not confirm a motor deficit less than Grade 5. Subset analysis showed that the L3-4 and L4-5 levels were most often affected. Conclusions: The minimally invasive, transpsoas muscle approach to the lumbar spine has a number of advantages. The data show that a percentage of the patients undergoing the transpsoas approach will have temporary sensory and motor symptoms related to this approach. The majority of the symptoms are thought to be related to psoas muscle inflammation and/or stretch injury to the genitofemoral nerve due to the surgical corridor traversed during the operation. No major injuries to the lumbar plexus were encountered. It is important to educate patients prior to surgery of the possibility of these largely transient symptoms.

Zigler J.E.,The Texas Institute | Delamarter R.,Cedars Sinai Spine Center | Murrey D.,Ortho Carolina Spine Center | Spivak J.,New York University | Janssen M.,Spinal USA
Spine | Year: 2013

STUDY DESIGN.: Randomized controlled trial. OBJECTIVE.: Analyze the clinical outcomes at 5 years comparing cervical total disc replacement (TDR) with ProDisc-C (Synthes Spine USA Products; LLC, West Chester, PA) with anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA.: Previous reports of 2- and 4-year results have shown that ProDisc-C, a TDR for surgical treatment of patients experiencing single-level symptomatic cervical disc disease between C3 and C7, is safe and effective. METHODS.: Two hundred nine patients (103 ProDisc-C and 106 ACDF) from 13 sites were randomized and treated. Results including neck disability index, visual analog scale (VAS) neck and arm pain, Short Form-36 (SF-36), neurological examination, device success, adverse event occurrence, and VAS patient satisfaction were analyzed. RESULTS.: Demographics were similar between the 2 patient groups (ProDisc-C: 42.1 ± 8.4 yr, 44.7% males; ACDF: 43.5 ± 7.1 yr, 46.2% males). Rates of follow-up at 2 years were 98.1% ProDisc-C and 94.8% ACDF, and at 5 years 72.7% ProDisc-C and 63.5% ACDF. For all clinical outcomes for both groups, there was a statistically and clinically significant improvement at 2 and 5 years compared with baseline. At 5 years, ProDisc-C patients had statistically significantly less neck pain intensity and frequency. Both groups scored high VAS satisfaction scores at 5 years, with ProDisc-C 86.56 and ACDF 82.74. There were no reports of device failures or implant migration with ProDisc-C. The ProDisc-C patients maintained motion at their index level. At 5 years, the ProDisc-C patients had a statistically significantly lower rate of reoperation compared with ACDF patients (2.9% vs. 11.3%). CONCLUSION.: Five-year results show that TDR with ProDisc-C is a safe and effective treatment of single-level symptomatic cervical disc disease. Clinical outcomes were comparable with ACDF. ProDisc-C patients maintained motion at the index level and had significantly less neck pain intensity and frequency as well as a lower probability of secondary surgery. © 2013, Lippincott Williams & Wilkins.

BACKGROUND:: Traditional surgical options for the treatment of symptomatic lumbar spinal stenosis include decompression alone vs decompression and fusion; both options have potential limitations. OBJECTIVE:: To report the 36-month follow-up analysis of the coflex Interlaminar Stabilization (Paradigm Spine, LLC, New York, New York) after decompression, examined under a Food and Drug Administration investigational device exemption clinical trial, which is intended to provide stabilization after decompression while preserving normal segmental motion at the treated level. METHODS:: The coflex trial was a prospective, randomized investigational device exemption study conducted at 21 clinical sites in the United States. Baseline and follow-up visits collected demographics, clinical, and radiographic status. The primary endpoint was a measure of composite clinical success 24 months postoperatively. For this current 36-month analysis, composite clinical success was calculated using analogous methods. RESULTS:: Composite clinical success at 36 months was achieved by 62.2% among 196 coflex Interlaminar Stabilization patients and 48.9% among 94 fusion patients (difference = 13.3%, 95% confidence interval, 1.1%-25.5%, P = .03). Bayesian posterior probabilities for noninferiority (margin = −10%) and superiority of coflex Interlaminar Stabilization vs fusion were >0.999 and 0.984, respectively. Substantial and comparable improvements were observed in both groups for patient-reported outcomes, although the percentage with a clinically significant improvement (≥15) in the Oswestry Disability Index seemed larger for the coflex Interlaminar Stabilization group relative to the fusion group (P = .008). Radiographic measurements maintained index level and adjacent level range of motion in coflex Interlaminar Stabilization patients, although range of motion at the level superior to fusion was significantly increased (P = .005). CONCLUSION:: Coflex Interlaminar Stabilization for stenosis is proven to be effective and durable at improving overall composite clinical success without altering normal spinal kinematic motion at the index level of decompression or adjacent levels. ABBREVIATIONS:: CCS, composite clinical successCEC, clinical events committeeFDA, Food and Drug AdministrationIDE, investigational device exemptionILS, Coflex Interlaminar StabilizationODI, Oswestry Disability IndexSF-12, Short-Form 12VAS, visual analogue scalesZCQ, Zurich Claudication Questionnaire Copyright © by the Congress of Neurological Surgeons

Bae H.W.,Cedars Sinai Spine Center | Bae H.W.,Spine Research Foundation | Rajaee S.S.,Spine Research Foundation | Rajaee S.S.,Tufts University | And 2 more authors.
Spine | Year: 2013

Objective. This study presents US nationwide trends in the surgical management of patients with lumbar spinal stenosis (LSS) with and without coexisting spondylolisthesis and scoliosis from 2004 to 2009. Summary of Background Data. Lack of consensus and wide variability exists in surgical decision making for patients with LSS. Methods. Data were obtained from the Nationwide Inpatient Sample, a database developed as part of the Healthcare Cost and Utilization Project. All discharged patients with a primary diagnosis of LSS were identified. Three subgroups were studied: (1) LSS alone, (2) LSS with spondylolisthesis, and (3) LSS with scoliosis. Surgical treatment was divided into 3 groups: (1) decompression only (laminectomy, discectomy), (2) simple fusion (1-2 disc levels, single approach), and (3) complex fusion (>2 disc levels or a combined posterior and anterior approach). Results. Between 2004 and 2009, national estimates for the annual number of discharged inpatients with a primary diagnosis of LSS increased from 94,011 (population rate, [the age adjusted population rate per 100,000] 32.1) to 102,107 (population rate, 33.3). The rate of decompressions decreased from 58.5% to 49.2% for discharged patients with LSS from 2004 to 2009 (P < 0.05), whereas the rate of simple fusions increased from 21.5% to 31.2% (P < 0.05) and the rate of complex fusions did not change at 6.7%. From 2004 to 2009, the use of bone morphogenetic protein more than doubled from 14.5% to 33.0% of all fusions, and the use of interbody devices increased from 28.5% to 45.1% (P < 0.05). In 2009, 26.2% of patients with LSS without instability underwent a fusion procedure, while 82.7% of patients with LSS with coexisting spondylolisthesis and 67.6% of patients with coexisting scoliosis underwent a fusion procedure. Conclusion. This study demonstrates that the rate of simple fusion surgery has increased for treatment of LSS compared with decompression only. Copyright © 2013 Lippincott Williams & Wilkins.

Delamarter R.B.,Cedars Sinai Spine Center | Zigler J.,The Texas Institute
Spine | Year: 2013

Study Design: Prospective randomized clinical trial. Objective: Determine the reasons for, and rates of, secondary surgical intervention up to 5 years at both the index and adjacent levels in patients treated with cervical total disc replacement (TDR) or anterior cervical discectomy and fusion (ACDF). Patients undergoing TDR received ProDisc-C. Summary of Background Data: Several outcome-based prospective, randomized clinical trials have shown cervical TDR to be equivalent, if not superior, to fusion. The ability of TDR to allow decompression while maintaining motion has led many to suggest that adjacent-level degeneration and reoperation rates may be decreased when compared with fusion. Methods: A total of 209 patients were treated and randomized (TDR, n = 103; ACDF, n = 106) at 13 sites. A secondary surgical intervention at any level was considered a reoperation. Results: At 5 years, patients who received ProDisc-C had statistically signifi cant higher probability of no secondary surgery at the index and adjacent levels than patients who underwent ACDF (97.1% vs. 85.5%, P = 0.0079). No reoperations in patients who received ProDisc-C were performed for implant breakages or device failures. For patients who underwent ACDF, the most common reason for reoperation at the index level was pseudarthrosis, and for patients who underwent both ACDF and TDR, the most common reason for adjacent-level surgery was recurrent neck and/or arm pain. Conclusion: Five-year follow-up of a prospective randomized clinical trial revealed 5-fold difference in reoperation rates when comparing patients who underwent ACDF (14.5%) with patients who underwent TDR (2.9%). These fi ndings suggest the durability of TDR and its potential to slow the rate of adjacent-level disease. Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

Zigler J.E.,The Texas Institute | Glenn J.,Core Orthopaedic Medical Center | Delamarter R.B.,Cedars Sinai Spine Center
Journal of Neurosurgery: Spine | Year: 2012

Object. The authors report the 5-year results for radiographically demonstrated adjacent-level degenerative changes from a prospective multicenter study in which patients were randomized to either total disc replacement (TDR) or circumferential fusion for single-level lumbar degenerative disc disease (DDD). Methods. Two hundred thirty-six patients with single-level lumbar DDD were enrolled and randomly assigned to 2 treatment groups: 161 patients in the TDR group were treated using the ProDisc-L (Synthes Spine, Inc.), and 75 patients were treated with circumferential fusion. Radiographic follow-up data 5 years after treatment were available for 123 TDR patients and 43 fusion patients. To characterize adjacent-level degeneration (ALD), radiologists at an independent facility read the radiographic films. Adjacent-level degeneration was characterized by a composite score including disc height loss, endplate sclerosis, osteophytes, and spondylolisthesis. At 5 years, changes in ALD (ΔALDs) compared with the preoperative assessment were reported. Results. Changes in ALD at 5 years were observed in 9.2% of TDR patients and 28.6% of fusion patients (p = 0.004). Among the patients without adjacent-level disease preoperatively, new findings of ALD at 5 years posttreatment were apparent in only 6.7% of TDR patients and 23.8% of fusion patients (p = 0.008). Adjacent-level surgery leading to secondary surgery was reported for 1.9% of TDR patients and 4.0% of fusion patients (p = 0.6819). The TDR patients had a mean preoperative index-level range of motion ([ROM] of 7.3° ) that decreased slightly (to 6.0° ) at 5 years after treatment (p = 0.0198). Neither treatment group had significant changes in either ROM or translation at the superior adjacent level at 5 years posttreatment compared with baseline. Conclusions. At 5 years after the index surgery, ProDisc-L maintained ROM and was associated with a significantly lower rate of ΔALDs than in the patients treated with circumferential fusion. In fact, the fusion patients were greater than 3 times more likely to experience ΔALDs than were the TDR patients. Clinical trial registration no.: NCT00295009.

Qureshi S.,Mount Sinai Medical Center | Goz V.,Mount Sinai Medical Center | McAnany S.,Mount Sinai Medical Center | Cho S.K.,Mount Sinai Medical Center | And 3 more authors.
Journal of Neurosurgery: Spine | Year: 2014

Object. Cost-effectiveness analysis (CEA) of medical interventions has become increasingly relevant to the discussion of optimization of care. The use of utility scales in CEA permits a quantitative assessment of effectiveness of a given intervention. There are no published utility values for degenerative disc disease (DDD) of the cervical spine, anterior cervical discectomy and fusion (ACDF), or cervical disc replacement (CDR). The purpose of this study was to define health utility values for those health states. Methods. The 36-Item Short Form Health Survey data from the ProDisc-C investigational device exemption study were obtained for single-level DDD at baseline and 24 months postoperatively after ACDF or CDR procedures. Patients in the original study were randomized to either ACDF or CDR. Utilizing a commercially available Short Form-6 dimensions program, utility scores were calculated for each health state using a set of parametric preference weights obtained from a sample of the general population using the recognized valuation technique of standard gamble. Results. The baseline health state utility (HSU) value for a patient with single-level DDD was 0.54 in both the ACDF and CDR groups. Postoperative changes in HSU values were seen in both intervention groups at 24 months. Cervical disc replacement had a HSU value of 0.72. Anterior cervical discectomy and fusion was found to have a postoperative utility state of 0.71. No statistically significant difference was found in the HSU for ACDF and CDR at 24 months of follow-up. Conclusions. This study represents the first calculated HSU value for a patient with single-level cervical DDD. Additionally, 2 common treatment interventions for this disease state were assessed. Both treatments were found to have significant impact on the HSU values. These values are integral to future CEA of ACDF and CDR. ©AANS, 2014.

Anand N.,Cedars Sinai Spine Center | Baron E.M.,Cedars Sinai Spine Center
Journal of Neurosurgery: Spine | Year: 2013

Transpsoas discectomy and interbody fusion has become an increasingly popular method of achieving lumbar interbody fusion, but reports of neurological, vascular, and gastrointestinal complications associated with this procedure have been described in the literature. To date, however, ureteral complications have not been reported with this procedure. The authors report 2 cases of ureteral injury and 1 case of renal injury following this procedure. A low index of suspicion is warranted to work up any patient having flank or abdominal symptoms after undergoing transpsoas discectomy and interbody fusion. ©AANS, 2013.

Rajaee S.S.,Spine Research Foundation | Rajaee S.S.,Cedars Sinai Spine Center | Rajaee S.S.,Tufts University | Bae H.W.,Spine Research Foundation | And 5 more authors.
Spine | Year: 2012

Study Design: Epidemiological study using national administrative data. Objective: To provide a complete analysis of national trends in spinal fusion from 1998 to 2008 and compare with trends in laminectomy, hip replacement, knee arthroplasty, percutaneous transluminal coronary angioplasty, and coronary artery bypass graft. Summary of Background Data: Previous studies have reported a rapid increase in volume of spinal fusions in the United States prior to 2001, but limited reports exist beyond this point, analyzing all spinal fusion procedures collectively. Methods: Data were obtained from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample for the years 1998 to 2008. Discharges were identified using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes for the following procedures: spinal fusion, laminectomy, hip replacement, knee arthroplasty, percutaneous transluminal coronary angioplasty, and coronary artery bypass graft. Population-based utilization rates were calculated from the US census data. Results: Between 1998 and 2008, the annual number of spinal fusion discharges increased 2.4-fold (137%) from 174,223 to 413,171 (P < 0.001). In contrast, during the same time period, laminectomy, hip replacement, knee arthroplasty, and percutaneous coronary angioplasty yielded relative increases of only 11.3%, 49.1%, 126.8%, and 38.8% in discharges, while coronary artery bypass graft experienced a decrease of 40.1%. Between 1998 and 2008, mean age for spinal fusion increased from 48.8 to 54.2 years (P < 0.001), in-hospital mortality rate decreased from 0.29% to 0.25% (P < 0.01), and mean total hospital charges associated with spinal fusion increased 3.3-fold (P < 0.001). The national bill for spinal fusion increased 7.9-fold (P < 0.001). Conclusion: Frequency, utilization, and hospital charges of spinal fusion have increased at a higher rate than other notable inpatient procedures, as seen in this study from 1998 to 2008. In addition, patient demographics and hospital characteristics changed significantly; in particular, whereas the average age for spinal fusion increased, the in-hospital mortality rate decreased.

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