A New High-Speed Shielded Curved Device Allowing Safe Posterior Thoracic Discectomy Through a Modified Transforaminal Thoracic Interbody Fusion Approach: Technique Description and Case Series.

BACKGROUND: The appropriate approach for surgical removal of thoracic disc herniations is controversial. The posterior approach historically acquired a bad reputation due to high rates of neurologic deterioration subsequent to spinal cord manipulation. The anterior approach has consequently gained popularity but entails a larger magnitude of surgery if open and is technically demanding if approached thoracoscopically. Approaching the thoracic disc posteriorly following unilateral facetectomy and pediculectomy was suggested in 1978. This study presents a technique for posterior unilateral thoracic discectomy through a hemilaminectomy, unilateral facetectomy, and hemipediculectomy, facilitated by a novel curved dorsally shielded high-speed device. Introducing the device ventral to the dural sac allows removal of calcified and soft disc fragments without relying on forceful manual maneuvers and avoiding manipulation of the spinal cord. METHODS: The maximal disc protrusion side is approached through a hemilaminectomy, unilateral facetectomy, and hemipediculectomy removing the superior half of the pedicle and exposing the disc transforaminally, allowing its removal using the device. Pedicle fixation and fusion concluded all procedures (TTIF). Between June 2014 and November 2018, 12 patients (6 men and 6 women) ages 23 to 74 years underwent posterior thoracic discectomy applying the above approach. The affected levels were D3 to D4 (1), D5 to D6 (1), D7 to D8 (1), D9 to D10 (1), D10 to D11 (3), D11 to D12 (4), and D12 to L1 (1). RESULTS: All patients presented with neurologic deterioration and all but 2 with pyramidal signs. All procedures were uneventful, without dural tears. None of the patients deteriorated neurologically. Average back pain visual analog scale scores decreased by 1.2, from 6.6 to 5.4. Average leg pain visual analog scale scores decreased by 2.2, from 6.6 to 4.4. Improvement was noted in Oswestry Disability Index scores and 6 SF-36 metrics. CONCLUSIONS: The new curved device and approach allow for a faster, safer thoracic disc herniation removal. CLINICAL RELEVANCE: The proposed technique allows a safer treatment for thoracic disc herniations, reducing complication rates and improving patient outcome.

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.

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.

Effect of an Outer Sleeve on an Inflatable Balloon Tamp in Terms of Height Restoration Under Simulated Physiological Load.

STUDY DESIGN: An in vitro biomechanical study. OBJECTIVE: The aim of this study was to determine the effect of an optional sleeve on height restoration and compare it with the fracture reduction achieved by a commercially available inflatable bone tamp under simulated physiological load (110 N). SUMMARY OF BACKGROUND DATA: Loss of reduction after bone tamp deflation before cement injection still remains a concern. The optional sleeve surrounds the bone tamp to help maintain height during the kyphoplasty procedure while filling the created cavity with bone cement on the contralateral side. METHODS: Eighteen osteoporotic vertebral bodies (VBs) (T11-L4) were alternately assigned to 1 of the 2 treatment groups: group A: KYPHON (Kyphon Inc.) and group B: AFFIRM with sleeve (Globus Medical Inc.). The VBs were compressed axially at a rate of 5 mm/min until compressed to 40% of the initial anterior height. The fractured VBs then underwent kyphoplasty with cement augmentation while still maintaining load (110 N). The augmented VBs were then recompressed and anterior VB height (mm) and wedge angle (degrees) were measured initially after mechanically creating an anterior wedge fracture, and after repairing the compression fracture. The effect of kyphoplasty on vertebral height, kyphotic angle, cement volumes, and inflation pressures were compared between the treatment groups. Failure load (N) data were compared between intact and repaired VBs. RESULTS: Average percentage of lost VB height restored in group A was 30%, compared with 56% for group B. The mean changes in wedge angle were similar to those of vertebral height measurements. No significant difference in mean inflation pressures (group A: 175±37 psi; group B: 160±36 psi) were found between the 2 groups. Average percentage increase in failure load was 241% and 212% in groups A and B, respectively. CONCLUSIONS: Some height restoration was observed using the commercially available bone tamp in fractured VBs under simulated physiological load. The use of an outer sleeve significantly enhanced height restoration compared with the inflatable bone tamp alone.

An In Vitro Evaluation of Fracture Reduction Achieved by Inflatable Bone Tamps Under Simulated Physiological Load.

STUDY DESIGN: An in vitro biomechanical study. OBJECTIVE: To determine the fracture reduction achieved by a novel inflatable bone tamp under simulated physiological load. SUMMARY OF BACKGROUND DATA: Previous biomechanical studies have showed that kyphoplasty allows near-total restoration of lost vertebral height in unloaded conditions and partial height restoration under simulated physiological loads. Clinically, loss of reduction has been observed after bone tamp deflation, before cement injection. The present study evaluated fracture reduction achieved by an inflatable bone tamp during kyphoplasty while maintaining physiological load. Comparison to commercially available inflatable bone tamp was also performed. MATERIALS AND METHODS: Eighteen osteoporotic vertebral bodies (T11-L4) were alternately assigned to one of the 2 treatment groups: group A-AFFIRM (Algea Thearpies, a division of Globus Medical Inc., Audubon, PA); and group B-KYPHON (Kyphon Inc., Sunnyvale, CA). The vertebral bodies were compressed axially on an MTS Bionix 858 machine at a rate of 5 mm/min until compressed to 40% of the initial anterior height. Load versus displacement was recorded. The fractured VBs then underwent kyphoplasty with cement augmentation. The augmented vertebral bodies were then recompressed and anterior vertebral body height (mm) and wedge angle (degrees) was measured initially, after mechanically creating an anterior wedge fracture, and after repairing the compression fracture. Each vertebral body was subjected to 111 N load to simulate in vivo physiological loading during inflation and cement augmentation. The vertebral height, wedge angle, cement volume, and inflation pressures were compared between the treatment groups using an unpaired t test (P<0.05). Failure loads were compared between intact and repaired VBs using a paired t test (P<0.05). RESULTS: Average lost height restored in group A was 29%, and 30% in group B compared to the compressed state. Similar trends were observed in the mean changes of vertebral body wedge angle in both the groups. No significant difference in mean inflation pressures (group A 182±33 psi; group B 175±37 psi) were found between the 2 groups. Average percentage increase in failure load was 218% and 241% for groups A and B, respectively. Mean injected cement volume was 6.65±0.65 and 6.73±0.41 mL for groups A and B, respectively. CONCLUSIONS: Some height restoration was observed using the 2 bone tamps in fractured vertebral bodies under simulated physiological load. The fracture reduction achieved by the 2 inflatable bone tamps was equivalent. No significant difference between mean inflation pressures and failure load was demonstrated between the 2 groups.

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.

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.

The biomechanical stability of a novel spacer with integrated plate in contiguous two-level and three-level ACDF models: an in vitro cadaveric study.

BACKGROUND CONTEXT: Anterior cervical plating increases stability and hence improves fusion rates to treat cervical spine pathologies, which are often symptomatic at multiple levels. However, plating is not without complications, such as dysphagia, injury to neural elements, and plate breakage. The biomechanics of a spacer with integrated plate system combined with posterior instrumentation (PI), in two-level and three-level surgical models, has not yet been investigated. PURPOSE: The purpose of the study was to biomechanically evaluate the multidirectional rigidity of spacer with integrated plate (SIP) at multiple levels as comparable to traditional spacers and plating. STUDY DESIGN: An in vitro cervical cadaveric model. METHODS: Eight fresh human cervical (C2-C7) cadaver spines were tested under pure moments of ±1.5 Nm on spine simulator test frame. Each spine was tested in intact condition, with only anterior fixation and with both anterior and PI. Range of motion (ROM) was measured using Optotrak Certus (NDI, Inc., Waterloo, Ontario, Canada) motion analysis system in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) at the instrumented levels (C3-C6). Repeated-measures analysis of variance was used for statistical analysis. RESULTS: All the surgical constructs showed significant reduction in motion compared with intact condition. In two-level fusion, SIP (C4-C6) construct significantly reduced ROM by 66.5%, 65.4%, and 60.3% when compared with intact in FE, LB, and AR, respectively. In three-level fusion, SIP (C3-C6) construct significantly reduced ROM by 65.8%, 66%, and 49.6% when compared with intact in FE, LB, and AR, respectively. Posterior instrumentation showed significant stability only in three-level fusion when compared with their respective anterior constructs. In both two-level and three-level fusion, SIP showed comparable stability to traditional spacer and plate constructs in all loading modes. CONCLUSIONS: The anatomically profiled spacer with integrated plate allows treatment of cervical disorders with fewer steps and less impact to cervical structures. In this biomechanical study, spacer with integrated plate construct showed comparable stability to traditional spacer and plate for two-level and three-level fusion. Posterior instrumentation showed significant effect only in three-level fusion. Clinical data are required for further validation of using spacer with integrated plate at multiple levels.

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.

Yeast strains with N-terminally truncated ribosomal protein S5: implications for the evolution, structure and function of the Rps5/Rps7 proteins.

Ribosomal protein (rp)S5 belongs to the family of the highly conserved rp's that contains rpS7 from prokaryotes and rpS5 from eukaryotes. Alignment of rpS5/rpS7 from metazoans (Homo sapiens), fungi (Saccharomyces cerevisiae) and bacteria (Escherichia coli) shows that the proteins contain a conserved central/C-terminal core region and possess variable N-terminal regions. Yeast rpS5 is 69 amino acids (aa) longer than the E. coli rpS7 protein; and human rpS5 is 48 aa longer than the rpS7, respectively. To investigate the function of the yeast rpS5 and in particular the role of its N-terminal region, we obtained and characterized yeast strains in which the wild-type yeast rpS5 was replaced by its truncated variants, lacking 13, 24, 30 and 46 N-terminal amino acids, respectively. All mutant yeast strains were viable and displayed only moderately reduced growth rates, with the exception of the strain lacking 46 N-terminal amino acids, which had a doubling time of about 3 h. Biochemical analysis of the mutant yeast strains suggests that the N-terminal part of the eukaryotic and, in particular, yeast rpS5 may impact the ability of 40S subunits to function properly in translation and affect the efficiency of initiation, specifically the recruitment of initiation factors eIF3 and eIF2.

Anterior lumbar fusion with paired BAK standard and paired 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.

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.

Airway complications associated with surgery on the anterior cervical spine.

STUDY DESIGN: Retrospective chart review of 311 anterior cervical procedures. OBJECTIVES: To assess the incidence and variables that predispose to an airway complication in a large series of anterior cervical surgical procedures. SUMMARY OF BACKGROUND DATA: A rare but potentially lethal complication after anterior cervical spine surgery is respiratory compromise and airway obstruction. Some risk factors are thought to include two-level corpectomy in myelopathic patients with a history of heavy smoking and asthma. No previous study in the literature has been directed at examining the factors specifically related to airway complications after anterior cervical spine surgery. METHODS: Each chart was examined for patient characteristics and pathology, anesthetic parameters and problems, operative procedure, and postoperative course and management. Statistical analysis was performed. RESULTS: Nineteen patients (6.1%) had an airway complication and six (1.9%) required reintubation. One patient died. Symptoms developed on average 36 hours postoperatively. All complications except for two were attributable to pharyngeal edema. Variables that were found to be statistically associated with an airway complication (P < 0.05) were exposing more than three vertebral bodies, a blood loss >300 mL, exposures involving C2, C3, or C4, and an operative time >5 hours. A history of myelopathy, spinal cord injury, pulmonary problems, smoking, anesthetic risk factors, and the absence of a drain did not correlate with an airway complication. CONCLUSIONS: Patients with prolonged procedures (i.e., >5 hours) exposing more than three vertebral levels that include C2, C3, or C4 with more than 300-mL blood loss should be watched carefully for respiratory insufficiency.