Moderate scoliosis continues to progress at 30-year follow-up: a call for concern?

PURPOSE: This natural history study reports long-term radiographic and clinical outcomes of patients with diagnosis of AIS with curves between 30° and 50°. Our purpose was to determine if any intervention in the natural history is warranted. METHODS: This was a longitudinal descriptive study at a single institution. We reviewed patient factors, radiographic parameters, and patient-reported outcomes at 20- and 30-year follow-up. RESULTS: A total of 31 patients were included. At skeletal maturity (which was the initial point of measurement), the median age was 17 years (range 12-21), the thoracic Cobb angle was 35° ± 5° (maximum-minimum 27°-47°), and the lumbar Cobb angle was 33° ± 7° (maximum-minimum 18°-45°). The median final follow-up was 35 years (median age 52, range 32-61) when the thoracic Cobb angle was 47° ± 12° (maximum-minimum 31°-74°) and the lumbar Cobb angle was 40° ± 17° (maximum-minimum 19°-69°). At final follow-up, 9 (29%) patients had a structural curve > 50°. Ten (32%) patients had a curve from 40° to 49° and 11 (35%) patients had a curve < 40°. The thoracic Cobb angle had progressed from < 40° to > 50° in 5 patients. Thoracolumbar and lumbar Cobb angles progressed from < 40° to greater than > 50° in 1 and 3 patients, respectively. Few patients had functional limitations according to Roland-Morris, Oswestry, and SF36 scores. Pain scores were minimal at final follow-up. CONCLUSION: All AIS curves between 30° and 50° at skeletal maturity tend to progress. Thoracic curves progress more than lumbar curves during the first 20 years and then progression slows down. The opposite happens with lumbar curves. Therefore, the rate of progression decreases with thoracic curves and increases with lumbar curves. Nevertheless, few patients have functional limitations. Further follow-up is necessary to define the true long-term outcome of moderate curves at maturity.

Removal of Spinal Instrumentation Is Not Required to Successfully Treat Postoperative Wound Infections in Most Cases.

INTRODUCTION: Controversy exists regarding whether spinal implants need to be removed to treat postoperative deep wound infections (DWIs). This retrospective study aimed to determine whether the removal or retention of implants impacts the successful treatment of a DWI after spine surgery. METHODS: Postoperative spine surgery patients presenting with signs of infection who underwent irrigation and debridement (I&D) at Twin Cities Spine Surgeons at Abbott Northwestern Hospital, Minnesota, USA, were studied. First, the persistence of infection when implants were retained or removed was assessed. Second, we analyzed the persistence of infection with respect to the number of I&D, the use of vacuum-assisted closure (VAC) treatment, pseudoarthrosis status, and functional outcomes. RESULTS: One hundred thirty-five patients were included. Treatment of infection with retention of implants occurred in 64% (87/135); of these, 7% (6/87) had a persistent infection. Of patients with implant removal (36%, 48/135), 6% (3/48) had a persistent infection. Thus, we observed no difference between treatment with implants present compared to implants removed (p = 1.0). Fifty of the 135 patients (37%) received I&D and primary wound closure, and 85 (63%) patients received I&D and VAC treatment. There was no statistical difference between primary wound closure and VAC treatment (p = 0.15) with respect to persistence. Repeat I&D with VAC (three or more times) had a significantly lower rate of recurrence than those with two I&Ds. Pseudoarthrosis and persistent infection were unrelated. At minimum one-year follow-up, achieving a minimum clinically important difference in functional outcome was independent of persistent infection status. CONCLUSION: Persistent infection was unrelated to the retention of implants. When VAC treatment was deemed necessary, more than two I&Ds resulted in a significantly better cure for infection. Those with a persistent infection were no more likely to exhibit pseudoarthrosis than those with no persistent infection. All patients showed improvement in functional outcomes at minimum one-year follow-up.

Posterior cervical lateral mass screw fixation and fusion to treat pseudarthrosis of anterior cervical fusion.

STUDY DESIGN: Retrospective clinical cohort study. OBJECTIVE: To determine the efficacy of posterior lateral mass screw/rod fixation and fusion for the treatment of symptomatic pseudarthrosis of anterior cervical fusion. SUMMARY OF BACKGROUND DATA: Both anterior revision and posterior repair of cervical pseudarthrosis have been reported. To date, there is still debate in the literature as how the patient with symptomatic cervical pseudarthrosis should be addressed. METHODS: Thirty-eight consecutive patients with symptomatic anterior cervical pseudarthrosis were treated with posterior lateral mass screw/rod fixation and fusion. The average follow-up was 28 months (24 to 60 mo) and patients were assessed with clinical examination, questionnaires, flexion-extension lateral radiographs, and/or computed tomography scans. The clinical results were classified as excellent, good, fair, or poor, according to Zdeblick criteria. RESULTS: All patients achieved a solid radiographic fusion at the final follow-up. The result was excellent in 10 patients, good in 22, fair in 6, and poor in none. CONCLUSIONS: Patients with symptomatic cervical pseudarthrosis that develops after anterior cervical discectomy and fusion may be managed successfully with posterior lateral mass screw fixation and fusion.

Choose Wisely: Surgical Selection of Candidates for Outpatient Anterior Cervical Surgery Based on Early Complications Among Inpatients.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are attractive targets for transition to the outpatient setting. We assessed the prevalence of rapid responses and major complications in the inpatient setting following 1 or 2-level ACDFs and CDAs. We evaluated factors that may place patients at greater risk for a rapid response or a postoperative complication. METHODS: This was an institutional review board-approved, retrospective cohort study of adults undergoing 1 or 2-level ACDF or CDA at 1 hospital over a 2-year period (2018 and 2019). Data on patient demographic characteristics, surgical procedures, and comorbidities were collected. Rapid response events were identified by hospital floor staff and involved acute changes in a patient's clinical condition. Complications were events that were life-threatening, required an intervention, or led to delayed hospital discharge. RESULTS: In this study, 1,040 patients were included: 888 underwent ACDF and 152 underwent CDA. Thirty-six patients (3.5%) experienced a rapid response event; 22% occurred >24 hours after extubation. Patients having a rapid response event had a significantly higher risk of developing a complication (risk ratio, 10; p < 0.01) and had a significantly longer hospital stay. Twenty-four patients (2.3%) experienced acute complications; 71% occurred >6 hours after extubation. Patients with a complication were older and more likely to be current or former smokers, have chronic obstructive pulmonary disease, have asthma, and have an American Society of Anesthesiologists (ASA) score of >2. The length of the surgical procedure was significantly longer in patients who developed a complication. All patients who developed dysphagia had a surgical procedure involving C4-C5 or more cephalad. Patients with a rapid response event or complication were more commonly undergoing revision surgical procedures. CONCLUSIONS: Rapid response and complications are uncommon following 1 or 2-level ACDFs or CDAs but portend a longer hospital stay and increased morbidity. Revision surgical procedures place patients at higher risk for rapid responses and complications. Additionally, older patients, patients with chronic obstructive pulmonary disease or asthma, patients who are current or former smokers, and patients who have an ASA score of ≥3 are at increased risk for postoperative complications. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Symptomatic pseudarthrosis requiring revision surgery after 1- or 2-level ACDF with plating: peek versus allograft.

BACKGROUND: Polyetheretherketone (PEEK) and machined allograft interbody spacers are among devices used as fusion adjuncts in anterior cervical discectomy and fusion (ACDF). Most results are good to excellent but some patients develop pseudarthrosis. We compared the reoperation rates for pseudarthrosis following 1- or 2-level ACDF with PEEK or allograft cages. METHODS: This was a retrospective cohort study. We reviewed patients who underwent 1- or 2-level ACDF. The rate of subsequent surgery for pseudarthrosis was calculated for cases confirmed by computerized tomography. Patient-reported outcomes were collected at post-index surgery follow-up and post-revision ACDF follow-up. Radiographic parameters were assessed at a minimum of 1-year post-op on all patients. RESULTS: Two hundred and nine patients were included: 167 received allograft and 42 received PEEK. Subsidence was demonstrated in 31% of allograft and 29% of PEEK patients. There were no significant differences in clinical outcomes between allograft and PEEK groups. Clinical outcomes were not adversely affected by subsidence. Reoperation for pseudarthrosis was performed in 8% of allograft patients and 14% of PEEK patients (not statistically different). Improvement in patient-reported outcome was significantly better for patients without symptomatic post-operative pseudarthrosis. CONCLUSIONS: Both allograft and PEEK spacers are acceptable options for ACDF surgery. Similar clinical outcomes and rates of radiographic subsidence were found. Subsidence was not a factor in clinical outcomes. Reoperation for pseudarthrosis was associated with poor outcomes. A higher incidence of revision for symptomatic pseudarthrosis occurred in the PEEK group, but this was not statistically significant.

A concomitant posterior approach improves fusion rates but not overall reoperation rates in multilevel cervical fusion for spondylosis.

STUDY DESIGN: Retrospective comparative study of 2 approaches to multilevel fusion for cervical spondylosis in consecutive patients at a single institution. OBJECTIVE: To provide justification for a concomitant posterior approach in multilevel cervical fusion for spondylosis by demonstrating decreased pseudarthrosis and reoperation rates. SUMMARY OF BACKGROUND DATA: Among the factors that affect cervical rates is the number of levels, such that increasing the number of levels leads to lower fusion rates. Because of this, modifications have been sought to improve union in multilevel procedures. One option is an antero-posterior (AP) approach or circumferential arthrodesis. METHODS: Seventy-eight consecutive patients who underwent multilevel cervical fusion at a single institution and with minimum 2-year follow-up data were divided into an anterior-only group (anterior: n=55), and an AP group (AP: n=23). Union was assessed by surgical exploration, computerized tomography scan, and flexion-extension radiographs. The groups were compared in terms of pseudarthrosis rates and reoperation rates. RESULTS: Using chi(2) analysis, there was a significant difference in pseudarthrosis rates (anterior 38% vs. AP 0%; P<0.001), and reoperation rate for pseudarthrosis (anterior 22% vs. AP 0%; P=0.01). There were no differences in overall (anterior 36% vs. AP 30%; P=0.62) and early (anterior 15% vs. AP 26%; P=0.13) reoperation rates, but late reoperations were increased in the anterior group (24% vs. AP 4%; P=0.043). CONCLUSIONS: A concomitant posterior fusion significantly reduced the incidence of pseudarthrosis (0% vs. 38%) and pseudarthrosis-related reoperations (0% vs. 22%) compared with traditional anterior-only fusion. However, this did not translate to a difference in overall reoperation rates. The majority of reoperations in the AP group (86%) were performed within 6 months, whereas those in the anterior-only group (65%) were performed later, which was generally when a pseudarthrosis became evident.

Posterolateral Versus Transforaminal Interbody L4/5 Fusion: Correlation With Subsequent Surgery.

STUDY DESIGN: This is a retrospective cohort study. OBJECTIVE: To compare posterolateral versus transforaminal interbody fusion (PLF vs. PLF+TLIF) of the L4/5 segment regarding rates of subsequent surgery, clinical and radiographic parameters, and patient satisfaction. SUMMARY OF BACKGROUND DATA: Surgical treatment of lumbar stenosis, decompression with or without fusion, is an efficacious treatment in select patients. Reoperation is thought to be a problem after lumbar fusion. Despite multiple studies, the fusion method that minimizes the need for subsequent surgery has yet to be determined. MATERIALS AND METHODS: A retrospective cohort study was conducted on 89 patients who had an isolated L4/5 decompression and fusion, from January 2006 to 2012. All patients had stenosis and degenerative spondylolisthesis at the L4/5 level. All surgeries were performed at a single center, using either PLF (31 patients) or PLF+TLIF (58 patients) techniques. Preoperative and postoperative patient-reported outcome measures (Oswestry disability index, visual analog scale back pain, visual analog scale leg pain) and radiographic parameters (L4/5 lordosis and overall lumbar lordosis) were measured. Patient satisfaction was acquired via a questionnaire. Chart reviews and patient questionnaires were used to determine the incidence of subsequent lumbar surgery over a minimum follow-up of 5 years. RESULTS: At an average of 8.7 years follow-up, 2 of 31 patients in the PLF group had subsequent lumbar surgery, compared with 16 of 58 patients in the PLF+TLIF group (6% vs. 28%; P=0.02). There were no significant differences between groups with respect to sex, age, body mass index, tobacco, perioperative measures, patient-reported outcomes, or radiographic parameters (P>0.05). CONCLUSIONS: Both PLF and PLF+TLIF are effective fusion methods for L4/5 stenosis and spondylolisthesis. In this study, patients treated with PLF were less likely to undergo a subsequent lumbar surgery. More research is needed to determine which factors influence whether PLF or PLF+TLIF should be used in these patients. LEVEL OF EVIDENCE: Level III.

Revision lumbar arthrodesis for the treatment of lumbar cage pseudoarthrosis: complications.

STUDY DESIGN: A study documenting major complications encountered in revision procedures for lumbar cage pseudoarthrosis. OBJECTIVE: To document the perioperative complications associated with revision surgery for threaded cylindrical cage pseudoarthrosis. SUMMARY OF BACKGROUND DATA: Pseudoarthrosis after cylindrical cage placement manifests as persistent or recurrent pain and disability after surgery. Revision strategies include isolated posterior stabilization and posterior bone grafting, versus circumferential revision where an attempt is made to remove the cages anteriorly, followed by posterior stabilization and fusion. Potential complications associated with these revision procedures have not been adequately documented in the past. METHODS: Forty-seven consecutive patients with the diagnosis of cylindrical cage pseudoarthrosis were surgically treated with either a circumferential revision (AP) or an isolated posterior instrumented fusion (P). All intraoperative and postoperative complications were documented. Radiographic interbody fusion rates and preoperative and postoperative visual analog scale (VAS) scores were documented. RESULTS: Three of the AP patients, all with anterior cage placement at L5-S1, had iliac vein lacerations requiring repair. A fourth patient had a ureteral injury requiring subsequent nephrectomy. Three patients who underwent circumferential revision and 2 patients who had an isolated posterior procedure had postoperative complications, including 2 infections (1 AP and 1 P), 1 radiculopathy (P), and 2 patients with prolonged ileus (both AP). There was a statistically significant decrease in overall VAS scores postoperatively for the 2 groups using the paired t test (P<0.0001). There was no difference in either the preoperative (P=0.22) or 2-year postoperative (P=0.30) VAS scores between the AP and P groups [rank-sum (Mann-Whitney) t tests]. Interbody fusion was achieved in 79% (30 of 38 levels) in the AP group. The interbody fusion rate was 37% (8 of 22) for the P group. CONCLUSIONS: Circumferential revision including cage removal, structural allograft placement, and posterior stabilization is associated with increased perioperative complications. Although an anterior approach showed increased interbody fusion rates, this technique did not lead to more superior clinical outcomes based on VAS scores. It remains to be shown by larger prospective studies if there is a true difference in outcome between these 2 groups that will justify the increased perioperative morbidity associated with attempted cage removal.

Outcomes After Spine Surgery Among Patients Who Have Had Prior Bariatric Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: We hypothesized that spine surgery patients with a history of bariatric surgery do not differ in expectations of surgery, perceived benefit of surgical intervention, or physician determined outcome of surgery from patients with no history of bariatric surgery. METHODS: Patients seen in our spine clinic between January 1, 2 009 and December 30, 2 010 were reviewed. Included patients had a history of bariatric surgery and were 18 to 89 years old. We compared their expectations for recovery, self-perceived clinical outcome (Oswestry Disability Index [ODI] or Neck Disability Index [NDI] and visual analog scale [VAS]), satisfaction with surgery, and physician-perceived clinical outcome (Odom's criteria) to a matched cohort with no such history. Patients were matched by type of surgery (approach, levels, and procedure), diagnosis, sex, body mass index (BMI), weight category, age, and smoking status. RESULTS: Of 210 included patients, 89 underwent spine surgery. One bariatric patient could not be matched. Seventeen received cervical spine surgery; 71 received lumbar spine surgery. The 2 cohorts had similar expectations and satisfaction. Patients with no history of bariatric surgery tended to be more satisfied than the bariatric surgery patients, but not significantly so. ODI/NDI and VAS scores were statistically worse for the bariatric cohort. Differences were attributed to differences among lumbar spine surgery patients; neck surgery patients were not different. Odom's scores were not different between the two. CONCLUSIONS: Postoperative expectations and satisfaction of bariatric patients are similar to those of nonbariatric patients. Bariatric patients receiving lumbar spine surgery experienced inferior clinical outcomes compared with nonbariatric patients. Cervical spine surgery bariatric patients have similar clinical outcomes as nonbariatric patients.

MRI measurement of neuroforaminal dimension at the index and supradjacent levels after anterior lumbar interbody fusion: a prospective study.

BACKGROUND: Anterior interbody fusion has previously been demonstrated to increase neuroforaminal height in a cadaveric model using cages. No prior study has prospectively assessed the relative change in magnetic resonance imaging (MRI) demonstrated neuroforaminal dimensions at the index and supradjacent levels, after anterior interbody fusion with a corticocancellous allograft in a series of patients without posterior decompression. The objective of this study was to determine how much foraminal dimension can be increased with indirect foraminal decompression alone via anterior interbody fusion, and to determine the effect of anterior lumbar interbody fusion on the dimensions of the supradjacent neuroforamina. METHODS: A prospective study comparing pre- and postoperative neuroforaminal dimensions on MRI scan among 26 consecutive patients undergoing anterior lumbar interbody fusion without posterior decompression was performed. We studies 26 consecutive patients (50 index levels) that had undergone anterior interbody fusion followed by posterior pedicle screw fixation without distraction or foraminotomy. We used preoperative and postoperative MRI imaging to assess the foraminal dimensions at each operated level on which the lumbar spine had been operated. The relative indirect foraminal decompression achieved was calculated. The foraminal dimension of the 26 supradjacent untreated levels was measured pre- and postoperatively to serve as a control and to determine any effects after anterior interbody fusion. RESULTS: In this study, 8 patients underwent 1 level fusion (L5-S1), 12 patients had 2 levels (L4-S1) and 6 patients had 3 levels (L3-S1). The average increase in foraminal dimension was 43.3% (p < 0.05)-19.2% for L3-4, 57.1% for L4-5, and 40.1% for L5-S1. Mean pre- and postoperative supradjacent neuroforaminal dimension measurements were 125.84 mm(2) and 124.89 mm(2), respectively. No significant difference was noted (p > 0.05). CONCLUSIONS: Anterior interbody fusion with a coriticocancellous allograft can significantly increase neuroforaminal dimension even in the absence of formal posterior distraction or foraminotomy; anterior interbody fusion with a coriticocancellous allograft has little effect on supradjacent neuroforaminal dimensions.

Supervised exercise, spinal manipulation, and home exercise for chronic low back pain: a randomized clinical trial.

BACKGROUND CONTEXT: Several conservative therapies have been shown to be beneficial in the treatment of chronic low back pain (CLBP), including different forms of exercise and spinal manipulative therapy (SMT). The efficacy of less time-consuming and less costly self-care interventions, for example, home exercise, remains inconclusive in CLBP populations. PURPOSE: The purpose of this study was to assess the relative efficacy of supervised exercise, spinal manipulation, and home exercise for the treatment of CLBP. STUDY DESIGN/SETTING: An observer-blinded and mixed-method randomized clinical trial conducted in a university research clinic in Bloomington, MN, USA. PATIENT SAMPLE: Individuals, 18 to 65 years of age, who had a primary complaint of mechanical LBP of at least 6-week duration with or without radiating pain to the lower extremity were included in this trial. OUTCOME MEASURES: Patient-rated outcomes were pain, disability, general health status, medication use, global improvement, and satisfaction. Trunk muscle endurance and strength were assessed by blinded examiners, and qualitative interviews were performed at the end of the 12-week treatment phase. METHODS: This prospective randomized clinical trial examined the short- (12 weeks) and long-term (52 weeks) relative efficacy of high-dose, supervised low-tech trunk exercise, chiropractic SMT, and a short course of home exercise and self-care advice for the treatment of LBP of at least 6-week duration. The study was approved by local institutional review boards. RESULTS: A total of 301 individuals were included in this trial. For all three treatment groups, outcomes improved during the 12 weeks of treatment. Those who received supervised trunk exercise were most satisfied with care and experienced the greatest gains in trunk muscle endurance and strength, but they did not significantly differ from those receiving chiropractic spinal manipulation or home exercise in terms of pain and other patient-rated individual outcomes, in both the short- and long-term. CONCLUSIONS: For CLBP, supervised exercise was significantly better than chiropractic spinal manipulation and home exercise in terms of satisfaction with treatment and trunk muscle endurance and strength. Although the short- and long-term differences between groups in patient-rated pain, disability, improvement, general health status, and medication use consistently favored the supervised exercise group, the differences were relatively small and not statistically significant for these individual outcomes.

Cervical degenerative changes in idiopathic scoliosis patients who underwent long fusion to the sacrum as adults: incidence, severity, and evolution.

BACKGROUND: To date, there have been no published studies of the degenerative changes in the cervical spine in adult idiopathic scoliosis patients with thoracic and lumbar curves severe enough to require major reconstructive surgery. MATERIALS AND METHODS: The primary study group was 48 adult patients who had previously undergone a fusion from T10 or higher to the sacrum as an adult for idiopathic scoliosis. These were compared to 38 adults with unfused idiopathic scoliosis of 30 degrees -50 degrees and to 42 symptomatic adults presenting with cervical pain. Cervical degeneration was assessed using a new cervical degenerative index (CDI). RESULTS: The amount of degenerative change seen in the cervical spine in the long-fusion group was significantly higher at baseline (just prior to the fusion) than the two control populations and became much higher at a mean follow-up of 8.5 years. CONCLUSIONS: This unique subgroup of patients, those having fusion from the thoracic spine to the sacrum as adults for adolescent idiopathic scoliosis, had a high incidence and severity of degenerative changes in their cervical spine. Due to the presence of advanced cervical degenerative changes prior to the fusion, it is not possible to blame the fusion as the main cause for these findings. These changes are either related to the thoracic and lumbar deformities or are more likely due to this subgroup having a higher natural propensity for degenerative changes.

Cervical degenerative index: a new quantitative radiographic scoring system for cervical spondylosis with interobserver and intraobserver reliability testing.

BACKGROUND: The lack of a widely available scoring system for cervical degenerative spondylosis encouraged the authors to establish and validate a systematic quantitative radiographic index. MATERIALS AND METHODS: This study included intraobserver and interobserver reliability testing among three reviewers with different years of experience. Each observer independently scored four cervical radiographs of 48 patients at separate intervals, and statistical analysis of the grading was performed. RESULTS: There was high intraobserver and interobserver reliability between the two experienced observers. There was fair reliability between the less experienced observer and the more experienced observers. CONCLUSIONS: The cervical degenerative index appears to be a reliable and reproducible radiographic assessment of cervical spondylosis. The index will have direct applicability for longitudinal study of cervical spondylosis and may be clinically relevant as well.

Can c7 plumbline and gravity line predict health related quality of life in adult scoliosis?

STUDY DESIGN: This study prospectively evaluated the health related quality of life (HRQOL) of 73 adults presenting with scoliosis at a single institution, as related to their spinal (C7 plumbline) and global (gravity line) balance. OBJECTIVE: To assess the influence of sagittal and coronal balance on HRQOL in adult scoliosis. SUMMARY OF BACKGROUND DATA: Many surgeons believe that achieving adequate spinal balance is important in the management of adult spinal deformity, but the evidence supporting this concept remains limited. A previous study has found weak correlations between sagittal spinal balance and HRQOL in adult spinal deformity, but this finding has never been confirmed independently. In addition, although the use of the gravity line is gaining interest in the evaluation of global balance, it remains unknown if this parameter is associated with HRQOL. METHODS: During a 1-year period, 73 consecutive new patients presenting with unoperated adult scoliosis and requiring full spine standing radiographs were evaluated using a force plate in order to simultaneously assess the gravity line. All patients also completed the Oswestry Disability Index (ODI) questionnaire to assess the HRQOL. Spinal balance was evaluated from the C7 plumbline and global balance from the gravity line, respectively. C7 plumbline and gravity line were both assessed with respect to the posterosuperior corner of the S1 vertebral body and central sacral vertebral line in the sagittal and coronal plane, respectively. C7 plumbline and gravity line, as well as their relative position, were correlated with the ODI, using Spearman coefficients. RESULTS: Sagittal spinal (C7 plumbline) and global (gravity line) balance, as well as their relative position were significantly related to the ODI. A poor ODI (>34) was associated with a sagittal C7 plumbline greater than 6 cm, a sagittal gravity line greater than 6 cm, and a C7 plumbline in front of the gravity line. Correlations between coronal balance and the ODI were not statistically significant. CONCLUSION: Sagittal spinal and global balance was strongly related to the ODI in adults with scoliosis. The observed correlation coefficients were higher than those reported in the only previous study suggesting the detrimental association of positive sagittal balance on ODI in adult spinal deformity. Coronal spinal and global balance did not influence the ODI in the current study cohort. Thisstudy underlines the relevance of C7 plumbline and gravity line in the evaluation of spinal and global balance, and lends further support to the philosophy of achieving adequate sagittal balance in the management of adult spinal deformity, especially in patients older than 50 years old with degenerative scoliosis.

Perioperative complications in revision anterior lumbar spine surgery: incidence and risk factors.

STUDY DESIGN: This is a retrospective review of 129 consecutive anterior lumbar revision surgeries in 108 patients. It is a single-center, multi-surgeon study. OBJECTIVE: To determine occurrence rates and risk factors for perioperative complications in revision anterior lumbar fusion surgery. SUMMARY OF BACKGROUND DATA: Although complication rates from large series of primary anterior fusion procedures have been reported, reports of complication rates for revision anterior fusion procedures are relatively rare. Concern exists chiefly about the risk to vascular and visceral structures because of scar tissue formation from the original anterior exposure. METHODS: This was a retrospective review of 129 consecutive anterior revision lumbar surgeries in 108 patients operated between 1998 and 2003. There were 40 men and 68 women. The age of patients ranged from 25 to 83 (average 50.6 years). Patients were excluded if surgery was for tumor or infection. Patients were divided into 2 groups; those with revision surgery at the same level and those with revision surgery at an adjacent level. Outcome measures included all perioperative complications. Statistical analysis included Student t test and nonparametric sign-rank. RESULTS: The number of surgical levels treated for revision was similar between the 2 groups (1 level 69%; 2 levels 19%; 3 or more levels 12%). Revision cases at the same operative level had a higher overall complication rate (42%) compared with extensions (20%; P = 0.007). This difference was primarily because of vein lacerations (23.7% vs. 3.6%, P = 0.002). There were 2 ureteral problems, both successfully salvaged. There were no arterial injuries or deaths. CONCLUSION: Complication rates for revision lumbar surgery in this series were 3 to 5 times higher than reported for primary lumbar exposures. Complication rates were significantly higher for revision anterior lumbar fusions at the same segment, which were typically in the lower lumbar spine, compared with cases involving extensions, which were typically in the upper lumbar spine.

Prospective study of postoperative lumbar epidural hematoma: incidence and risk factors.

STUDY DESIGN: Prospective clinical series. OBJECTIVE: To determine the incidence, volume, and extent of postoperative epidural hematoma resulting in thecal sac compression, and to identify risk factors correlated with measured hematoma volumes. SUMMARY OF BACKGROUND DATA: Risk factors for postoperative hematoma development have been retrospectively determined in small populations of symptomatic patients. A prospective study of hematoma characteristics and associated risk factors in a consecutive series of patients could significantly enhance our understanding of postoperative hematoma. METHODS: Preoperative magnetic resonance imaging and clinical data on 13 pre- and intraoperative risk factors were prospectively collected on 50 consecutive patients undergoing lumbar decompression surgery with or without fusion. Postoperative magnetic resonance imagings were performed within 2 to 5 days of surgery. Thecal sac cross-sectional area was calculated at each disc space. Relative thecal sac compression due to hematoma was calculated at all levels where postoperative cross-sectional area was smaller than preoperative. Hematoma volumes were calculated. Multivariate analysis identified risk factors associated with postoperative hematoma volume. RESULTS: After decompression, 58% of patients developed epidural hematoma of sufficient magnitude to compress the thecal sac beyond its preoperative state at one or more levels. None developed new postoperative neurologic deficits. A mean of 1.4 levels were decompressed. Hematoma extended over a mean of 1.9 levels. Maximal thecal sac compression due to hematoma occurred at an adjacent, nondecompressed level in 28% of patients. Multivariate analysis found age greater than 60, multilevel procedures, and preoperative international normalized ratio to be associated with larger hematoma volumes. CONCLUSION: Lumbar decompression surgery results in a 58% incidence of asymptomatic compressive postoperative epidural hematoma. Adjacent level compression by hematoma occurs in 28% of patients. Advanced age, multilevel procedures, and international normalized ratio are independently associated with postoperative hematoma volume.

Postoperative lumbar epidural hematoma: does size really matter?

STUDY DESIGN: Prospective clinical series with comparison to retrospectively collected data. OBJECTIVE: To compare direct measures of postoperative hematoma volume against a new measure of hematoma effect on the thecal sac: the critical ratio. SUMMARY OF BACKGROUND DATA: Asymptomatic epidural hematoma is common after lumbar surgery. Symptomatic patients demonstrate a typical progression from sharp peri-incisional pain to bilateral neurologic deficits. Little is known about what differentiates symptomatic and asymptomatic patients. Magnetic resonance imaging (MRI) measures of hematoma size or mass effect may correlate with postoperative symptoms. METHODS: The study population consisted of 3 patient groups evaluated by MRI 2 to 5 days after lumbar decompression with or without fusion. Fifty-seven consecutive prospectively enrolled patients comprised the asymptomatic group. No patient developed severe postoperative pain or neurologic deficit. Search of our institutional database identified 4978 surgical patients within the last 24 months. Seventeen developed new postoperative symptoms. The painful group included 12 patients with severe peri-incisional pain without neurologic deficit. The cauda equina (CE) group included 5 patients with postoperative CE syndrome. Digital imaging software was used to calculate thecal sac cross sectional area on pre- and postoperative MRI at each level, hematoma volume, volume per level decompressed, and critical ratio for each patient. Critical ratio was defined as the smallest ratio of postoperative to preoperative cross sectional area within the lumbar spine. RESULTS.: The critical ratio was the only measure found to differ significantly (P < 0.05) among all 3 groups. Mean critical ratios were asymptomatic (0.8), painful (0.5), and CE (0.2). CONCLUSION: The critical ratio correlates more closely with the presence or absence of postoperative symptoms than measures of hematoma volume, and is consistent with the clinical expectation that greater thecal sac compression may result in more severe symptoms. Few guidelines exist for postoperative lumbar MRI interpretation. The critical ratio is an important contribution.

Complications in long fusions to the sacrum for adult scoliosis: minimum five-year analysis of fifty patients.

STUDY DESIGN: A retrospective study of complications with minimal 5-year follow-up of 50 adults with scoliosis with fusion from T10 or higher to S1. OBJECTIVES: To document the perioperative and long-term complications and instrumentation problems, and to attempt to determine variables which may influence these problems. It is not a study of curve correction, balance, or functional outcome. SUMMARY OF BACKGROUND DATA: Several previous studies from this and other centers have shown a relatively high complication rate for this select group of patients. Various fusion techniques (anterior, posterior, autograft, allograft), various instrumentation techniques, and various immobilization techniques have created confusion as to the best methodology to employ. Minimal 2-year follow-ups have been standard, but longer follow-ups have shown additional problems. METHODS: The study cohort consisted of 50 adult patients from a single center who had undergone corrective scoliosis surgery from T10 or higher to the sacrum and who had at least a 5-year minimum follow-up. The mean age was 54 years (range, 18-72), and the mean follow-up was 9.7 years (range, 5-26). All radiographs, office charts, and hospital charts were combed by an independent investigator for complications, which were divided into major and minor, as well as early, intermediate and late. The curvature values and corrections were the subject of a different article, and were not included in this study. RESULTS: There were no deaths or spinal cord injuries. Six patients had nerve root complications, 4 of which totally recovered. Pseudarthrosis was seen in 24% of the patients, only 25% of which were detected within the 2-year follow-up period. Pseudarthrosis was most common at the lumbosacral level. There was no statistical difference in the pseudarthrosis rate between patients with sacral-only fixation versus iliac fixation. Painful implants requiring removal were noted in 11 of the 50 patients. CONCLUSION: Long fusions to the sacrum in adults with scoliosis continue to have a high complication rate. As compared to the original publications in the 1980s (Kostuik and Hall, Spine 1983;8:489-500; Balderston et al, Spine 1986;11:824-9) the more recent articles have shown a reduction, but not elimination of the pseudarthrosis problem using segmental instrumentation and anterior fusion of the lumbar spine coupled with structural interbody grafting at L4-L5 and L5-S1. Two-year follow-up is inadequate as pseudarthrosis and painful implants often are detected later. Only 3 of the 12 patients with pseudarthrosis were detected within the first 2 years after surgery.

Stepwise methodology for plain radiographic assessment of pedicle screw placement: a comparison with computed tomography.

OBJECTIVE: The objective of this study is to evaluate the effectiveness of a specific methodology for plain radiographic assessment of lumbar pedicle screw position. PURPOSE: To evaluate the effectiveness of using orthogonal plain radiographs and a systematic method of interpretation, developed by the senior author, in assessing the placement of lumbar and lumbosacral pedicle screws. STUDY DESIGN: This was an adult cadaver study of the accuracy of using plain radiographs or computed tomography to assess pedicle screw position. Plain radiographs were performed and compared with computed tomography (CT) scans. Gross anatomic dissections were performed to directly confirm screw position. Variables, including screw material, radiographic view, and screw dimensions, were assessed for their effect on the ability of physicians to determine pedicle screw position. Multiple readers were included in the study, including 1 spine Fellow, 3 experienced orthopedic spine surgeons, and 1 neuroradiologist. METHODS: Five adult cadaveric spines were instrumented with titanium pedicle screws from L1 to S1. Screws were placed outside the confines of the pedicle in all 4 quadrants or within the pedicle using a Latin-Square design. Each cadaver was imaged with orthogonal radiographs and high-resolution CT scans. The spines were then reimaged after the instrumentation was replaced with stainless steel screws placed in the identical position. Finally, each spine was dissected to assess the exact position of the screws. Images were read in a blinded fashion by 1 spine fellow, 2 staff surgeons, and a staff radiologist. The results were compared with the known screw positions at dissection. RESULTS: In total, 120 pedicle screws were placed, 44 (38%) outside the confines of the pedicle. Sensitivity, defined as the percent of the misplaced screws that were correctly identified, was similar across the 3 diagnostic tests, but markedly improved when all CT formats were considered together. Similarly, specificity, defined as the percent of screws correctly read as being placed within the pedicle, was independent of radiographic examination. Sensitivity of the radiographic technique was 70.1% and specificity was 83.0%, whereas sensitivity for CT scans was 84.7% and specificity was 89.7%. There was an observed association with anatomic level, with a consistently less accuracy in detecting screw position at L1 with plain x-ray (P=0.001). Additionally, correct position of stainless steel screws was more difficult to detect as compared with titanium (P=0.033) using either x-rays or CT. Other variables examined, such as screw length and screw diameter, did not have an effect on the ability to read the positioning. CONCLUSIONS: CT scans, often considered the "gold standard" for clinical assessment of pedicle screw placement, have limitations when validated with gross anatomical dissection. The described systematic method for evaluating pedicle screw placement using orthogonal plain radiographs attained accuracy comparable to high-resolution CT scans.

Outcome of anterior cervical discectomy and fusion as perceived by patients treated for dominant axial-mechanical cervical spine pain.

STUDY DESIGN: An extensive outcome questionnaire using a visual analog scale, the North American Spine Society Satisfaction Questionnaire, a Modified Roland and Morris disability index, and a modified Oswestry Disability Index was used to assess the outcome of anterior cervical discectomy and fusion for those with neck pain. OBJECTIVE: To document the clinical outcome for 87 patients who underwent anterior cervical discectomy and fusion for the primary indication of neck pain, as assessed after an average follow-up period of 4.4 years. SUMMARY OF BACKGROUND DATA: Clinical outcome studies of anterior cervical discectomy and fusion with validated patient-perceived outcome measurements are few. METHODS: From the authors' database, 87 patients were identified who had undergone an anterior cervical discectomy and fusion for primary indication of dominant neck pain, and who had completed an extensive outcome questionnaire regarding pain and self-function at a mean 4.4-year follow-up assessment. RESULTS: This study documents a self-perceived satisfactory outcome rate of 82%. Patients reported on improvement of pain using visual analog scales, on function using modified Oswestry and modified Roland-Morris disability indexes, and on satisfaction using the North American Spine Society outcome tool. On an assessment 4.4 years on the average after the surgery, 82% of the patients (71/87) self-perceived their outcome to be good, very good, or excellent. Pain improvement was reported by 93% of the patients (81/87), whose average visual analog rating changed from 8.4 before surgery to 3.8 after surgery. The self-rated functional status improved approximately 50% on both the Oswestry and the modified Roland-Morris disability indexes. CONCLUSIONS: Properly selected patients who present with a primary indication of chronic neck pain report a high percentage of change in their self-perceived level of pain and function when treated with anterior cervical discectomy and fusion. Patients' self-expressed improvement with surgical management, as compared with their preoperative dissatisfaction because of their neck condition, documents that this surgical treatment is a reasonable option.