William Beutler

The Natural History of Spondylolysis and Spondylolisthesis: 45-year Follow-up Evaluation

Study Design. A prospective study of spondylolysis and spondylolisthesis was initiated in 1955 with a radiographic and clinical study of 500 first-grade children. Objective. To determine the natural history of spondylolysis and spondylolisthesis. Summary of Background Data. Most studies on the natural history of spondylolysis and spondylolisthesis are based on patient populations presenting with pain. Critical to any natural history investigation is the study of a population of affected individuals, whether symptomatic or not, from onset of the condition through their lives. Methods. By study of a population from the age of 6 years to adulthood, 30 individuals were identified to have pars lesions. Data collection at a 45-year follow-up assessment included magnetic resonance imaging, a back pain questionnaire, and the SF-36 Survey. Results. No subject with a pars defect was lost to follow-up evaluation once a lesion was identified. Subjects with unilateral defects never experienced slippage over the course of the study. Progression of spondylolisthesis slowed with each decade. There was no association of slip progression and low back pain. There was no statistically significant difference between the study population SF-36 scores and those of the general population the same age. Conclusions. This report is the only prospective study to document the natural history of spondylolysis and spondylolisthesis from onset through more than 45 years of life in a population unselected for pain. Subjects with pars defects follow a clinical course similar to that of the general population. There appears to be a marked slowing of slip progression with each decade, and no subject has reached a 40% slip.

Anterior lumbar fusion with paired BAK standard andpaired BAK Proximity cages: subsidence incidence, subsidence factors,and clinical outcome

BACKGROUND CONTEXT Anterior lumbar interbody fusion (ALIF) procedures have a known incidence of subsidence. The individual risk of subsidence for specific lumbar levels in ALIF procedures has not been determined. PURPOSE To evaluate the incidence of subsidence with two ALIF constructs. A paired Bagby and Kuslich (BAK) standard cage construct is compared with a paired BAK Proximity construct (Sulzer Spine-Tech, Minneapolis, MN). Study purpose is to evaluate lumbar intervertebral disc subsidence including the subsidence incidence for each disc level and with single- and two-level constructs. Also evaluated is the site of maximal subsidence within each end plate, risk with increased reaming depth, fusion incidence and clinical outcome. STUDY DESIGN A consecutive series of 70 fused levels fused with paired standard BAK cages is compared with a subsequent series of 70 fused levels using paired Proximity BAK cages. PATIENT SAMPLE The study population is derived from a consecutive series of ALIF procedures completed by a single surgeon. In 1998 the construct was changed from dual-standard to dual-Proximity cages. In the year 2000 there were 52 patients with a 2-year follow-up. These were matched to the previous 52 patients with dual-standard construct. OUTCOME MEASURES Clinical outcome was determined using pre- and postoperative Oswestry questionnaires. Postoperative questionnaires were completed at the yearly follow-up. Radiographic outcome was determined by fusion status and evaluation of subsidence. Also evaluated was reaming depth and cage size for each fused level. METHODS A total of 52 patients with ALIF procedures using paired BAK standard cages (the SS group) were studied with a group of 52 patients using paired BAK Proximity cages (the PP group). The study population was derived from an ongoing prospective study of consecutive ALIF fusion procedures completed by a single surgeon. Disc height measurements were used to determine subsidence. Reaming depth, fusion status and the site of maximal subsidence were all recorded. Clinical outcome was determined with a pre- and postoperative Oswestry functional questionnaire. RESULTS Subsidence greater than 2 mm was noted in 5 of the 70 SS fused levels and in 9 of the 70 fused PP levels. Subsidence was always at the L4-L5 level in the SS subsided levels. Subsidence was in two-level fusions in all but one of the SS constructs. Subsidence was at the L4-L5 level in eight of the nine subsided PP levels. Subsidence was associated with increased reaming depth and the use of larger cage sizes. Subsidence was usually in the posterior and superior end plate. The clinical outcome was not affected by subsidence. Subsidence incidence was not associated with the age, sex or weight of the patient. CONCLUSIONS There is a statistically significant increased incidence of subsidence at the L4-L5 level as opposed to other fused lumbar levels in ALIF fusions with BAK cage constructs. There is an increased incidence of subsidence with the PP constructs. Subsidence also is associated with increased reaming depth and with larger cage sizes. The lowest risk for subsidence was with single-level dual-standard cage constructs.

Clinical Outcomes With Selectively Constrained Secure-c Cervical Disc Arthroplasty: Two-year Results From a Prospective, Randomized, Controlled, Multicenter Investigational Device Exemption Study

Study Design. Prospective, multicenter, randomized, and controlled Investigational Device Exemption clinical trial. Objective. To compare the clinical safety and effectiveness of the selectively constrained SECURE-C (Globus Medical, Audubon, PA) Cervical Artificial Disc to anterior cervical discectomy and fusion (ACDF). Summary of Background Data. Cervical total disc replacement has been developed as an alternative to ACDF by allowing segmental motion. Current cervical total disc replacement designs incorporate constrained and unconstrained metal-on-metal or metal-on-polymer articulating designs with various means of fixation. Methods. A total of 380 patients from 18 investigational sites were prospectively enrolled in the study. Patients were randomized, treated surgically, and evaluated postoperatively at 6 weeks, 3 months, 6 months, 12 months, and 24 months. Clinical outcomes include overall success, visual analogue scale pain (right arm, left arm, and neck), neck disability index, neurological status, Short Form 36 (SF-36) Health Status Survey questionnaires, range of motion, and adverse events. Bayesian statistical methods were used to analyze the outcomes. Results. Overall success results demonstrated statistical superiority of the randomized SECURE-C group compared with the randomized ACDF group at 24 months, with a posterior probability of 100% using the protocol-specified criteria and 98.1% using Food and Drug Administration-defined criteria. At 24 months postoperatively, SECURE-C demonstrated clinically significant improvement in pain and function in terms of neck disability index, visual analogue scale, and 36-Item Short Form Health Survey. At 24 months, the percentage of patients experiencing secondary surgical interventions at the index level was statistically lower for the SECURE-C group (2.5%) than the ACDF group (9.7%). At 24 months, 84.6% of as-treated SECURE-C patients were range-of-motion successes. Satisfaction was high among SECURE-C patients. Conclusion. The selectively constrained SECURE-C Cervical Artificial Disc is as safe and effective as the standard of care, an anterior cervical discectomy and fusion. SECURE-C is statistically superior in terms of overall success, index-level subsequent surgical procedures, and patient satisfaction, making it an attractive surgical option for patients with symptomatic cervical disc disease. Level of Evidence: 1

Clinical experience using Cortoss for treating vertebral compression fractures with vertebroplasty and kyphoplasty: twenty four-month follow-up.

Study Design. Forty patients were enrolled in 2 FDA-approved pilot Investigational Device Exemption (IDE) studies using Cortoss for the treatment of vertebral compression fractures (VCF). Twenty patients were treated at 3 centers, using vertebroplasty (VP) and 20 patients were treated at 5 centers, using kyphoplasty (KP). Objective. To assess the feasibility and clinical outcomes using Cortoss to treat osteoporotic VCF. Summary of Background Data. Cortoss is an injectable bioactive, self-setting, radiopaque composite shown to stabilize and provide immediate weight bearing support to fractured vertebrae. Cortoss is approved for use in Europe for both screw and vertebral augmentation. Methods. Patient assessments were conducted before surgery and after surgery through 24 months using Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and quality-of-life assessment (SF-12) questionnaires. Extravasations were evaluated using radiographs and CT scans. Results. Immediate pain improvement was seen in VP patients with VAS scores decreasing from 75.7 before surgery to 35.9 at 72 hours. Continued improvement from baseline was seen out to 2 years (average VAS of 48.9). Disability improved with average ODI scores decreasing from 52.2% preoperative to 38.3% at 2 years for VP patients. Immediate pain improvement was also seen in KP patients with VAS scores decreasing from 78.1 before surgery to 42.7 at 72 hours. Continued improvement from baseline was seen out to 2 years (average VAS of 25.4). ODI scores improved from 60.5% preoperative to 34.5% at 2 years for KP patients. Average material volumes injected were 1.85 mL for VP and 4.13 mL for KP. Extravasations from both techniques were minor, anatomically close to the treated vertebrae and asymptomatic. No cardiac irregularities or pulmonary emboli were observed. Conclusion. These studies indicate Cortoss is safe and effective in treating osteoporotic VCF using vertebroplasty or kyphoplasty. Pain relief and restoration of function with Cortoss is comparable to results found in the literature for polymethylmethacrylate.

The da Vinci robotic surgical assisted anterior lumbar interbody fusion: technical development and case report.

Study Design. Technique development to use the da Vince Robotic Surgical System for anterior lumbar interbody fusion at L5–S1 is detailed. A case report is also presented. Objective. To evaluate and develop the da Vinci robotic assisted laparoscopic anterior lumbar stand-alone interbody fusion procedure. Summary of Background Data. Anterior lumbar interbody fusion is a common procedure associated with potential morbidity related to the surgical approach. The da Vinci robot provides intra-abdominal dissection and visualization advantages compared with the traditional open and laparoscopic approach. Methods. The surgical techniques for approach to the anterior lumbar spine using the da Vinci robot were developed and modified progressively beginning with operative models followed by placement of an interbody fusion cage in the living porcine model. Development continued to progress with placement of fusion cage in a human cadaver, completed first in the laboratory setting and then in the operating room. Finally, the first patient with fusion completed using the da Vinci robot–assisted approach is presented. Results. The anterior transperitoneal approach to the lumbar spine is accomplished with enhanced visualization and dissection capability, with maintenance of pneumoperitoneum using the da Vinci robot. Blood loss is minimal. The visualization inside the disc space and surrounding structures was considered better than current open and laparoscopic techniques. Conclusion. The da Vinci robot Surgical System technique continues to develop and is now described for the transperitoneal approach to the anterior lumbar spine. Level of Evidence: 4

A biomechanical evaluation of a spacer with integrated plate for treating adjacent-level disease in the subaxial cervical spine

BACKGROUND CONTEXT Adjacent level degeneration (ALD) has been reported as one of the long-term consequences of anterior discectomy and fusion despite its clinical success in treating cervical pathologies. Traditionally, ALD is treated by replacing the previously implanted plate with a longer plate, which can lead to postoperative complications. The biomechanics of SIP in the adjacent level has not been investigated. PURPOSE To evaluate the multidirectional stability of a spacer with integrated plate (SIP) in comparison to a traditional spacer and plate (TSP). STUDY DESIGN To evaluate the biomechanical stability of a spacer with integrated plate adjacent to a traditional spacer and plate construct in a human cervical cadaveric model. METHODS Eight fresh human cervical (C2-C7) cadaver spines were mounted on a six degree-of-freedom spine simulator. The sequence of test constructs was: 1) Intact; 2) TSP (C4-C6) with SIP (C3-C4); and 3) TSP (C3-C6). An unconstrained moment of ±1.5 Nm was used in flexion-extension, lateral bending, and axial rotation. Range of motion (ROM) was measured by a digital motion analysis system. Statistical analysis was performed using ANOVA repeated measures. RESULTS All instrumented constructs significantly reduced ROM compared to the intact condition. No statistically significant difference was observed between the two-level TSP with an adjacent SIP construct and three-level TSP construct in all loading modes. CONCLUSION The biomechanical study shows that adding a spacer with integrated plate adjacent to a two-level anterior plate demonstrates equivalent stability to a three-level anterior plate. The spacer with integrated plate, which preserves the originally plated fusion levels, may overcome the complications associated with the traditional technique of replacing the original plate with a longer plate. However, prospective clinical studies are required to address the clinical benefits and challenges, if any.

Long-Term Clinical Experience with Selectively Constrained SECURE-C Cervical Artificial Disc for 1-Level Cervical Disc Disease: Results from Seven-Year Follow-Up of a Prospective, Randomized, Controlled Investigational Device Exemption Clinical Trial

ABSTRACT Background: This research was initiated to compare the long-term clinical safety and effectiveness of the selectively constrained SECURE-C (Globus Medical, Audubon, Pennsylvania) Cervical Artificial Disc to anterior cervical discectomy and fusion (ACDF). To preserve segmental motion, cervical total disc replacement (CTDR) was developed as an alternative to ACDF. Current CTDR designs incorporate constrained and unconstrained metal-on-metal or metal-on-polymer articulation with various means of fixation. Methods: Eighteen investigational sites participated in this prospective clinical trial; 380 patients were enrolled and treated in the investigational device exemption study. The first 5 patients treated at each site were nonrandomized and received the investigational SECURE-C device. Patients were randomized, treated surgically, and evaluated postoperatively at 6 weeks, 3 months, 6 months, 12 months, 24 months, and annually thereafter through 84 months postoperative. Results: Overall results for the randomized cohorts demonstrated statistical superiority of the investigational SECURE-C group over the control ACDF group at 84 months postoperative. SECURE-C showed clinically significant improvement in pain and function in terms of neck disability index and visual analog scale scores, and superiority in patient satisfaction was also achieved for patients treated with SECURE-C. Conclusion: Clinical study results indicated that the selectively constrained SECURE-C Cervical Artificial Disc is as safe and effective as ACDF. Long-term results from the Post Approval Study demonstrated that SECURE-C is statistically superior to ACDF in terms of overall success and patient satisfaction. Lower rates of subsequent index-level surgeries and device-related adverse events were observed in the SECURE-C group than in the ACDF group. The long-term, level 1 clinical evidence presented here is consistent with other reports supporting the safety and efficacy of cervical arthroplasty, and furthers advocacy for motion preservation as a viable alternative to fusion.

Wednesday, October 30, 2001 9:08–9:51 amGeneral Session 3: Outcomes—Nonoperative Versus Operative 9:08 Assessment of lumbar interbody fusion status by discogram technique: rate of concordant pain response, determination of pseudarthrosis and results of revision surgery

Abstract Purpose of study: The determination of the etiology of persistent pain after lumbar interbody fusion is often difficult, especially with metallic interbody constructs. Our study evaluates a unique discogram technique for determination of interbody fusion status. We evaluate the rate of concordant pain response on injection of interbody fusion constructs. We also determine the results of revision surgery after discogram evidence of failed fusion. Methods used: Twenty-four patients were referred for evaluation of lumbar interbody fusion and adjacent levels by discogram technique. Referrals noted appearance of solid fusion on standard radiographic studies but persistent low back pain. Adjacent levels were evaluated in addition to the level of interbody fusion. Presenting symptom was predominantly low back pain (n=24) with variable lower extremity symptoms. Pseudarthrosis was dramatically documented when dye flowed around and through interbody cages or surrounded allograft arthrodesis. Solid arthrodesis was documented with inability to inject dye or with dye flowing around solid construct. A retrospective review of prereferral studies noted the appearance of fusion with lack of halo formation, appearance of bone incorporating into the vertebral bodies and less than 5 degrees of motion on flexion–extension lateral radiographs. When pseudarthrosis with concordant response was documented, patients were given the option of revision surgery. Clinical response to revision surgery was evaluated independently by a questionnaire completed by the patient. A minimum of 2-year follow-up postoperatively was required for study inclusion. of findings: Twenty-four patients (16 women, 8 men) with persistent postoperative low back pain and appearance of solid fusion on standard radiographs underwent discogram evaluation of interbody fusion and adjacent levels. All patients were sent a back pain questionnaire by an independent reviewer with a 79% (17 of 24) response. Average time from fusion to the discogram study was 17 months. Pseudarthrosis was demonstrated in 58% (14 of 24) of the patients evaluated. Concordant pain response was seen in only one level that was documented solid on interbody discogram. Any level with pseudarthrosis was always accompanied by a concordant pain response (p Relationship between findings and existing knowledge: Studies have noted pseudarthrosis intraoperatively in levels noted solid on standard radiographic studies. McAfee demonstrated a wide variation in techniques used to document solid fusion. We provide an additional technique to evaluate lumbar interbody fusion. Overall significance of findings: The interbody fusion discogram provides a dramatic demonstration of pseudarthrosis in patients with persistent low back pain, despite appearance of solid fusion on standard radiographs. There is a strong statistical correlation of concordant pain response and discogram documentation of pseudarthrosis. Interbody fusion discogram technique allows demonstration of pseudarthrosis, documents response at adjacent levels and predicts successful outcome with revision surgery. Disclosures: No disclosures. Conflict of interest: No conflicts.