Does pelvic incidence tell us the risk of proximal junctional kyphosis in adult spinal deformity surgery?

PURPOSE: To investigate the relationship between pelvic incidence (PI) and proximal junctional kyphosis (PJK) in patients treated surgically for adult spinal deformity (ASD) with fusion from thoracolumbar junction to sacrum. METHODS: A consecutive series of ASD patients who underwent fusion from the thoracolumbar junction to the sacrum with a minimum of 2-year follow-up was studied. Patients were divided into low PI (≤ 50°) and high PI (> 50°) groups. We compared radiographic parameters and the rates of PJK, between the two groups. A sub-analysis was performed on patients with a postoperative PI minus lumbar lordosis mismatch between - 10° and 10° (i.e., ideally corrected). RESULTS: Sixty-three patients were included: 19 low PI and 44 high PI. Median follow-up was 34 months (range 24-103). Overall PJK rate was 38%. PJK was observed in 16% of low PI and 48% of high PI patients (p = 0.02). The odds ratio for developing PJK with a high PI compared to a low PI was 4.9 (p = 0.03). There were 32 ideally corrected patients. Eleven of these were in the low PI group, and 21 patients were in the high PI group. The incidence of PJK was 25% for ideally corrected patients. PJK occurred in none of these patients in the low PI group and 38% of patients in the high PI group (p = 0.03). CONCLUSION: When the upper-instrumented vertebra includes the thoracolumbar junction, patients with a PI > 50° are at a significantly higher risk of developing PJK compared to patients with a PI ≤ 50°.

Anterioposterior Views Coupled With Lateral Views Are the Best for the Intraoperative Radiographic Detection of Retained Surgical Sponges.

INTRODUCTION: A retained sponge after spine surgery can cause serious medical complications and medicolegal problems. Intraoperative radiographs are commonly used to detect it. This study evaluated intraoperative radiographs under routine clinical conditions that most spine surgeons experience to detect retained sponges. METHODS: In this prospective randomized clinical trial, two patient groups undergoing open posterior lumbar surgery were studied. In one, a sponge was intentionally present; in the other, none was present. Standard intraoperative lateral (LAT) and anteroposterior (AP) radiographs were acquired before closing. Radiographs were analyzed for sensitivity, specificity, inter- and intraobserver reliability for three viewing conditions: one LAT radiograph versus one AP radiograph versus one LAT and one AP X-ray (LAT+AP). RESULTS: A total of 111 patients were included. Accuracy, interobserver reliability, and intraobserver reliability were best for LAT+AP (80%, 96%, and 96%, respectively). Sensitivity was best for LAT+AP (87%) and specificity was best for LAT (95%). Positive predictive value was best for LAT (94%); negative predictive value was best for LAT+AP (88%). The probability of being right is better for female sex (odds ratio 1.6), younger age (odds ratio 1.02), and higher BMI (odds ratio 1.06). CONCLUSIONS: We recommend AP with LAT images rather than either an AP or a LAT image alone.

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.

Provocative Discography: Diagnostic Efficacy and Safety in Symptomatic Degenerative Disk Disease.

STUDY DESIGN: This was a retrospective cohort analysis. OBJECTIVE: The objective of this study was to report the efficacy and safety profile of provocative discography. SUMMARY OF BACKGROUND DATA: It is reported that the provocative discogram as a diagnostic test for symptomatic degenerative disk disease induces disk degeneration. MATERIALS AND METHODS: Discogram cases from 1998 to 2011 were identified. A matched control group with no discogram was identified. Both had pre-magnetic resonance imaging (MRI) and post-MRI with 5 years minimum between MRI studies. Statistics were generated by group for each level and for all levels combined. RESULTS: The discogram cohort comprised 53 patients (193 disks). The control group had 51 subjects (255 disks). There were no significant demographic differences between the groups. Time intervals between the index and follow-up MRI were 11 and 8 years for the discogram and control groups, respectively. The most common injected level was L4-L5; the most painful level was L5-S1 (Visual Analog Scale=7.9); the most concordant level was L5-S1 (75%). The most deranged level as seen on discography was L5-S1 (98%). Degeneration from normal to abnormal MRI among discogram patients was 60%. For controls, the rate was 33%. The discogram and control cohorts were statistically different (P<0.01). Among discogram patients, 58% had a fusion surgery between MRI studies. Comparing the discogram group without interval fusion to controls, the degeneration rate was not different at a 5 years' minimum follow-up. CONCLUSIONS: The L5-S1 intervertebral disk level was the most painful, concordant, and deranged level as seen on discogram. Patients who underwent a provocative discogram and interval fusion had a higher rate of subsequent degeneration than similar low back pain sufferers with no discogram. Degeneration rates were comparable at 5 years' minimum follow-up between discogram patients without interval spine fusion and patients without discogram exposure. The provocative discogram did not accelerate degeneration among these patients.

Surgical Treatment of Single Level Cervical Radiculopathy: A Comparison of Anterior Cervical Decompression and Fusion (ACDF) Versus Cervical Disk Arthroplasty (CDA) Versus Posterior Cervical Foraminotomy (PCF).

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The objective of this study is to retrospectively compare the clinical outcomes, complication rates, and reoperation rates among the 4 treatments in patients with cervical radiculopathy. SUMMARY OF BACKGROUND DATA: Surgical options for cervical radiculopathy include anterior cervical discectomy and fusion (ACDF), open posterior cervical foraminotomy (O-PCF), minimally invasive posterior cervical foraminotomy (MI-PCF), and cervical disk arthroplasty (CDA). MATERIALS AND METHODS: Retrospective chart review after Review Board approval. Of the 384 patients in the study-257 ACDF, 18 O-PCF, 52 MI-PCF, and 56 CDA. Information was obtained from the charts and compared between the groups. PATIENT SAMPLE: Patients above 18 years of age with single-level, unilateral cervical radiculopathy correlating with magnetic resonance imaging, failure of nonoperative management, and 1-level ACDF, O-PCF, MI-PCF, or CDA with >24 months of follow-up. OUTCOME MEASURES: Neck Disability Index (NDI), Visual Analog Score neck and arm pain, minimum clinically significant difference (MCID), complication rates, and reoperation rates. RESULTS: Operative time was significantly shorter for MI-PCF. Median estimated blood loss was small, but greater with O-PCF compared with other interventions. The length of hospital stay was longest for the ACDF group. At 2 years' follow-up, 36 subjects (9%) had subsequent neck surgery. The most common indication for additional surgery was recurrent symptoms (3.4%) followed by adjacent segment disease (2.6%), pseudoarthrosis (2.1%), adjacent segment disease + pseudoarthrosis (0.5%), and implant-related complications (0.3%). There was no statistically significant difference in complication rates between groups. MCID in NDI was achieved in 40% of MI-PCF subjects, 42% of O-PCF subjects, 66% of CDA subjects and 46% of ACDF subjects. CONCLUSIONS: All 4 treatment options confer good clinical results on patients for cervical radiculopathy. Intraoperative and postoperative complications were low and comparable in all 4 groups. MI-PCF had the shortest surgical time and length of hospital stay. More CDA patients achieved MCID in NDI compared with the others, and the rate for additional surgery at 2 years was lowest in the CDA group.

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.

In vivo biostability of polymeric spine implants: retrieval analyses from a United States investigational device exemption study.

The Dynesys System for stabilizing the lumbar spine was first surgically implanted in Europe in 1994. In 2003, a prospective, randomized, investigational device exemption clinical trial of the system for non-fusion dynamic stabilization began. Polycarbonate urethane (PCU) and polyethylene terephthalate (PET) components explanted from four patients who had participated in the study were analyzed for biostability. Components had been implanted 9-19 months. The explanted components were visually inspected and digitally photographed. Scanning electron microscopy was used to analyze the surface of the spacers. The chemical and molecular properties of the retrieved spacers and cords were quantitatively compared with lot-matched, shelf-aged, components that had not been implanted using attenuated total reflection Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). FTIR analyses suggested that the explanted spacers exhibited slight surface chemical changes but were chemically unchanged below the surface and in the center. New peaks that could be attributed to biodegradation of PCU were not observed. The spectral analyses for the cords revealed that the PET cords were chemically unchanged at both the surface and the interior. Peaks associated with the PET biodegradation were not detected. GPC results did not identify changes to the distributions of molecular weights that might be attributed to biodegradation of either PCU spacers or PET cords. The explanted condition of the retrieved components demonstrated the biostability of both PCU spacers and PET cords that had been in vivo for up to 19 months.

Do Preoperative Nasal Antiseptic Swabs Reduce the Rate of Surgical Site Infections After Adult Thoracolumbar Spine Surgery?

INTRODUCTION: Surgical site infection (SSI) remains a major complication after adult spinal surgery. We investigated whether adding preoperative nasal decontamination by antiseptic swab (skin and nasal antiseptic povidone-iodine, SNA-PI) to our antimicrobial protocol reduces the SSI rate among our patients undergoing thoracolumbar spinal surgery. METHODS: We retrospectively reviewed all adult thoracolumbar spinal surgeries performed between June 2015 and May 2017 at a single hospital. Patients were divided into those who received nasal decontamination (SNA-PI+) and those who did not (SNA-PI-). SSI rates and responsible pathogens were compared between the cohorts. RESULTS: A total of 1,555 surgeries with nasal decontamination (SNA-PI+) and 1,423 surgeries without (SNA-PI-) were included. The SSI rate in the SNA-PI+ group was 13 of 1,555 (0.8%) versus 10 of 1,423 (0.7%) for SNA-PI- group (P = 0.68). The infection rate was the highest among posterior instrumented fusions in the SNA-PI+ group (1.4%). Methicillin-sensitive Staphylococcus aureus was responsible for 70% of infections in the SNA-PI- group and 38% in the SNA-PI+ group (P = 0.13). CONCLUSIONS: Routine nasal antiseptic swab before spine surgery did not affect the overall rate of SSI in thoracolumbar spinal surgeries. The incidence of methicillin-sensitive S aureus was lower in patients who received nasal decontamination (5/1,555, 0.3%) compared with those who did not (7/1,423, 0.5%); however, this result was not statistically significant (P = 0.57).

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.

Complications with Minimally Invasive Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis in the Obese Population.

STUDY DESIGN: A level-3 retrospective cohort analysis. OBJECTIVE: The aim of this study was to describe obesity's effect on complications and outcomes in degenerative spondylolisthesis patients treated by minimally invasive transforaminal lumbar interbody fusion (MI TLIF). SUMMARY OF BACKGROUND DATA: Obesity is associated with a greater complication rate among lumbar spine surgery patients. Poor clinical outcomes might likewise be supposed, but the association is not well established. Minimally invasive techniques have been developed to reduce complications and improve clinical outcomes in comparison to traditional open techniques. METHODS: We reviewed 134 consecutive patients with degenerative spondylolisthesis undergoing MI TLIF. Subjects were grouped into nonobese (N = 65) and obese (N = 69) cohorts. The obese group was further subdivided by BMI. Patient demographics, perioperative complications, and outcome scores were collected over a minimum of 24 months. Four periods (intraoperative, postoperative hospitalization, 6-month, and 24-month postoperative) were assessed. RESULTS: Cohort demographics were not significantly different, but it was noted that obese patients had more major comorbidities than nonobese patients. There was no difference in intraoperative complications between the two groups. The in-hospital complication rate was significantly greater in the obese group. The 6-month postoperative complication rate was not different between cohorts. Wound drainage was most common and noted only in the obese cohort. Complications at 24 months were not different but did trend toward significance in the obese for recurrence of symptoms and total complications. Functional outcome was better among nonobese subjects compared with obese subjects at every interval (significant at 6 and 12 months). Back pain scores were significantly better among nonobese subjects than obese subjects at 24 months, but Leg Pain scores were not different. CONCLUSIONS: MI TLIF can be safely performed in the obese population despite a higher in-hospital complication rate. Knowledge of common complications will help the treatment team appropriately manage obese patients with degenerative spondylolisthesis. LEVEL OF EVIDENCE: 3.

Treatment of degenerative spondylolisthesis by instrumented posterolateral versus instrumented posterolateral with transforaminal lumbar interbody single-level fusion.

BACKGROUND: The purpose of this study was to compare outcomes of patients with degenerative spondylolisthesis treated by posterolateral lumbar fusion (PLF) versus PLF with transforaminal lumbar interbody fusion (PLF + TLIF). Studies of PLF versus PLF + TLIF have shown either equivalence or support for PLF + TLIF in lumbar spine surgery. Many are heterogeneous in the conditions treated, with few considering only spondylolisthesis of degenerative origin. Radiographic outcomes tend to favor PLF + TLIF, but this has not translated into better clinical outcomes. METHODS: This was a retrospective cohort study. Forty-nine patients undergoing single-level PLF and seventy patients undergoing single-level PLF + TLIF with two-year follow-up were retrospectively reviewed. Demographics, Oswestry Disability Index (ODI), implant cost, surgical data, and complications were analyzed. RESULTS: There was no difference in ODI improvement at two-year follow-up between the cohorts (P=0.97). Dural tears were more common in the PLF cohort (P<0.01), but otherwise complication and reoperation rates were similar. Implant cost (P<0.01) and operative time (P=0.01) were higher in the PLF + TLIF cohort. CONCLUSIONS: The addition of a TLIF to a PLF did not result in a functional improvement in the treatment of degenerative spondylolisthesis as measured by the ODI.

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.

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.

Clinical and Radiologic Comparison of Minimally Invasive Surgery With Traditional Open Transforaminal Lumbar Interbody Fusion: A Review of 452 Patients From a Single Center.

STUDY DESIGN: Retrospective analysis of prospective data for parallel, consecutive series of patients (Level III). OBJECTIVE: Compare clinical results and radiographic outcomes of minimally invasive surgery (MIS) versus open techniques for transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: Minimally invasive techniques allow transforaminal exposure with decreased soft tissue disruption, but the question remains whether surgical and functional outcomes are equivalent to open techniques. MATERIALS AND METHODS: A consecutive series of 452 1 or 2-level TLIF patients at a single institution between 2002 and 2008 were analyzed. A total of 148 were MIS patients and 304 were open. Operative time, estimated blood loss, infection rate, and hospital length of stay were recorded. Oswestry disability index (ODI) and visual analog (VAS) pain scores were documented preoperatively and postoperatively. Fusion was assessed radiologically at a minimum of 1 year follow-up. RESULTS: There were proportionally more 2-level than 1-level procedures in the open group compared with the MIS group; there were more Workers' Compensation patients among 1-level procedures than 2-level. There were more Spondylolisthesis patients and fewer Degenerative Disk Disease patients among one-level procedures compared with 2-level. Blood loss and operative time were lower in the MIS group. Length of hospital stay in the MIS cohort was shorter compared with the open cohort. There were 3 deep wound infections in the open cohort. ODI and VAS (leg and back) scores improved in both groups at 1 year compared with preoperative scores and did not differ between MIS and open cohorts. Fusion rate was similar for both groups (91% overall). One-level procedures and BMP use were associated with higher fusion rate, regardless of approach. CONCLUSIONS: MIS TLIF produces comparable clinical and radiologic outcomes to open TLIF with the benefits of decreased intraoperative blood losses, shorter operative times, shorter hospital stays, and fewer deep wound infections.

Validation of the Fusion Risk Score for Thoracic and Lumbar Spine Fusion Procedures.

STUDY DESIGN: This is a retrospective cohort study. OBJECTIVE: This study aimed to determine whether the Fusion Risk Score (FRS) is valid for perioperative complications. SUMMARY OF BACKGROUND DATA: The FRS was previously formulated from a retrospective review of 364 fusion surgeries in patients over age 65. Patient demographics, comorbidities, surgical approach, levels, and osteotomies are incorporated in a weighted manner. This score correlated well with the risk of perioperative complications, operative time, estimated blood loss during surgery, and length of hospital stay. MATERIALS AND METHODS: A new cohort of patients was studied. Subjects were 65 years old or older and had undergone routine elective thoracic or lumbar fusion surgery. The FRS was calculated for each subject to estimate risk (low, medium, or high) for perioperative complications. Actual incidences of major complications in the first 90 days after the surgery were noted and statistically compared with the predicted risk. The FRS was compared with intensive care unit admittance, estimated blood loss, operative time, and hospital length of stay to determine whether the score was predictive. RESULTS: In total, 51% of our patients were at low risk (FRS, 1-3) for perioperative complications; 43% were at medium risk (FRS, 4-9); and 7% were at high risk (FRS, over 9). A total of 8% in the low-risk group, 23% in the medium-risk group, and 67% in the high-risk group actually developed significant perioperative complications. Medium-risk and high-risk patients experienced proportionally more perioperative complications than did low-risk patients; the difference was highly statistically significant. CONCLUSIONS: This study validated the association between the FRS and complications in the first 90 days after thoracolumbar spinal fusion surgery on the basis of patient and surgery characteristics. It also predicts the risk of intensive care unit admission, operative time, blood loss, and hospital length of stay.

Recurrent Surgical Site Infections in the Spine After Treatment With the Vacuum-assisted Closure (VAC) System.

STUDY DESIGN: This study retrospectively reviewed recurrences of surgical site infections (SSI) in spinal patients treated with vacuum-assisted closure (VAC) technology. OBJECTIVE: Identify patient and treatment factors associated with recurrence of SSI after VAC treatment. SUMMARY OF BACKGROUND DATA: Patients treated with VAC can achieve healing of deep spine wound infections; however, some patients develop a recurrent infection. Risk factors associated with a recurrence have not been identified. MATERIALS AND METHODS: One hundred and eleven patients with SSI after spine surgery from 2002 to 2010 were studied. They had been treated with irrigation and debridement, placement of VAC, and IV antibiotics. They subsequently were taken to surgery for primary closure of their wound. Patients with SSI who healed after the initial infection treatment were compared with patients who experienced recurrence. Patient and treatment factors that were studied included smoking status, body mass index, obesity status, diagnosis of diabetes, fusion surgery, methicillin-resistant Staphylococcus aureus, or polybacteria infection, number of irrigation and debridement treatments before closure, duration of IV antibiotic treatment, and duration of treatment time with VAC. Patients with SSI who healed after the initial treatment were compared with patients who experienced recurrence. RESULTS: Fourteen patients had at least one recurrence of wound infection. None of the patient or treatment factors was associated with the recurrence of a SSI. CONCLUSIONS: Among spine surgery patients with a SSI treated with the VAC system, those factors which predispose a patient to develop a recurrent SSI remain unknown. LEVEL OF STUDY: Level IV.

The peroneal tubercle: description, classification, and relevance to peroneus longus tendon pathology.

BACKGROUND: The size and configuration of the peroneal tubercle has been implicated in the pathogenesis of peroneal tendon tears and tenosynovitis. The purpose of this study was to determine the size and prevalence of the peroneal tubercle and devise a classification scheme according to the structure of the tubercle. METHODS: One hundred and seventeen calcanei were selected from 59 human skeletons in an osteological collection (one calcaneus was missing). Three were excluded because of the poor condition, leaving 114 calcanei. The peroneal tubercle was measured in length, height, and depth and its structure subjectively described as flat, prominent, concave, or tunnel for each specimen when present. RESULTS: This study revealed a peroneal tubercle prevalence of 90.4% (103) in 114 calcanei. The average length, height, and depth of the tubercle were 13.04 mm (range 3.61 mm to 26.66 mm), 9.44 mm (range 3.67 mm to 23.40 mm), and 3.13 mm (range 1 to 10), respectively. The peroneal tubercle was classified structurally as flat in 44 (42.7%), prominent in 30 (29.1%), concave in 28 (27.2%), and tunnel in one (1.0%). CONCLUSION: This data may further help to understand the size and assorted configurations of the peroneal tubercle and how they relate to peroneus longus tendon pathology.

The biomechanical response to doses of TGF-beta 2 in the healing rabbit medial collateral ligament.

Ligament injuries result in significant disability in over 100,000 patients each year. Despite current methods of treatment, 13% of patients with medial collateral ligament (MCL) injury develop early signs of arthritis, suggesting an incomplete return of knee stability. The principal hypothesis of this work was that the addition of TGF-beta 2 to the healing MCL would accelerate the development of scar strength and stiffness. Forty-four rabbits were divided evenly into four groups, with each group receiving either 0.1, 1 or 5 microg of TGF-beta 2 and the fourth group receiving 1 microg TGF-beta 2 and 1 microg of PDGF. Each rabbit underwent bilateral transection of the MCL, with one side having treatment with one of four doses of growth factor and the other side left untreated. All animals were sacrificed at 6 weeks and the structural properties of maximum load at failure, stiffness, and energy absorbed at failure measured. All treatment groups demonstrated an increase in scar mass, but no group had a significant increase in scar load at failure at 6 weeks. The addition of 0.1 microg TGF-beta 2 led to a significant increase in scar stiffness. The addition of PDGF had no significant effect on any of the parameters studied. This study suggests the mechanical stiffness, but not the load at failure, of ligament scar can be significantly altered by the administration of TGF-beta 2.