Is the likelihood of dysphagia different in patients undergoing one-level versus two-level anterior cervical discectomy and fusion?

BACKGROUND CONTEXT: Dysphagia following anterior cervical discectomy and fusion (ACDF) is a common complication, the etiology of which has not been established. Given that one potential mechanism for dysphagia is local tissue edema, it is thought that a greater number of operative levels may result in higher dysphagia rates. However, prior reports comparing one-level to two-level ACDF have shown varying results. PURPOSE: To determine if there is a difference in dysphagia between one-level and two-level ACDF. STUDY DESIGN/SETTING: Retrospective review of prospectively collected data. PATIENT SAMPLE: Patients who underwent one- or two-level ACDF with a plate-graft construct by a single-surgeon at a high-volume academic medical center. OUTCOME MEASURES: Neck Disability Index, Visual Analog Scale for neck pain and arm pain, Short Form-12 physical and mental health components, and Swallowing Quality of Life (SWAL-QOL) Questionnaire. METHODS: Patient demographics, operative data, and patient-reported outcome measures (PROMs; Neck Disability Index, Visual Analog Scale, Short Form-12, and SWAL-QOL) of patients undergoing one- and two-level ACDF were compared using Fisher exact test for categorical variables and Student's t test for continuous variables. Regression analyses were conducted to identify factors associated with 6- and 12-week SWAL-QOL scores in order to determine whether the number of surgical levels impacts these outcomes. RESULTS: Fifty-eight patients (22 one-level and 36 two-level ACDF) were included. Patients undergoing two-level fusions were older (54.17+8.67 vs 48.06+10.68 years, p=.02) and had longer operative times (69.08+10.51 vs 53.5+14.35 minutes, p<.0001). There were no other significant differences in demographics or operative data. Both groups showed a statistically significant improvement in PROMs from preoperatively to 12 weeks. There was no difference in PROMs or dysphagia rates between groups at any time-point. Younger age (p=.023), male sex (p=.021), longer operative times (p=.068), and worse preoperative SWAL-QOL (p<.0001) were associated with dysphagia at 6 weeks. Preoperative SWAL-QOL was the only variable associated with dysphagia at 12 weeks (p=.003). Operative time of >61.5 minutes had a sensitivity and specificity of 62.1% for worse dysphagia scores at 6 weeks compared with baseline. CONCLUSIONS: The results of our study indicate that there is no difference in the degree of postoperative dysphagia in one- versus two-level ACDF. However, other variables associated with increased postoperative dysphagia in our population included younger age, male sex, procedural time >61.5 minutes, and worse preoperative dysphagia. Larger studies are required to confirm these findings and identify additional risk factors for postoperative dysphagia.

Retrospective Review of Immediate Restoration of Lordosis in Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Comparison of Static and Expandable Interbody Cages.

BACKGROUND: Sagittal alignment is an important consideration in spine surgery. The literature is conflicted regarding the effect of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) on sagittal parameters and the role of expandable cage technology. OBJECTIVE: To compare lordosis generated by static and expandable cages and to determine what factors affect postoperative sagittal parameters. METHODS: Preoperative regional lordosis (RL), segmental lordosis (SL), and posterior disc height (PDH) were compared to postoperative values in single-level MI-TLIF performed using expandable or static cages. Patients were stratified based on preoperative SL: low lordosis (<15 degrees), moderate lordosis (15-25 degrees), and high lordosis (>25 degrees). Regression analyses were conducted to determine factors associated with postoperative SL and PDH. RESULTS: Of the 171 patients included, 111 were in the static and 60 in the expandable cohorts. Patients with low preoperative lordosis experienced an increase in SL and maintained RL regardless of cage type. Those with moderate to high preoperative lordosis experienced a decrease in SL and RL with the static cage, but maintained SL and RL with the expandable cage. Although both cohorts showed an increase in PDH, the increase in the expandable cohort was greater. Preoperative SL was predictive of postoperative SL; preoperative SL, preoperative PDH, and cage type were predictive of postoperative PDH. CONCLUSION: Expandable cages showed favorable results in restoring disc height and maintaining lordosis in the immediate postoperative period. Preoperative SL was the most significant predictor of postoperative SL. Thus, preoperative radiographic parameters and goals of surgery should be important considerations in surgical planning.

Predictive Factors of Postoperative Dysphagia in Single-Level Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To investigate if zero profile devices offer an advantage over traditional plate/cage constructs for dysphagia rates in single level anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Dysphagia rates following ACDF have been reported to be as high as 83%, most cases are self-limiting, but chronic dysphagia can continue in up to 35% of patients. Zero profile devices were developed to limit dysphagia, and other plate specific complications, however the literature is currently divided regarding their efficacy. METHODS: Dysphagia was assessed by swallowing quality of life (SWAL-QOL) scores preoperatively, at 6 weeks and 12 weeks. Patient reported outcome measures (PROMs) including visual analog scale (VAS) and Neck Disability Index (NDI) were collected preoperatively, at 6 weeks and at 6 months. Univariate and multivariate regression analysis was conducted with SWAL-QOL score as the dependent variable. RESULTS: Sixty-four patients were included, 41 received a zero profile device, and 23 received plate-graft construct. Both groups were similar regarding patient demographics, except operative time, with the zero-profile group having a shorter procedure time than the cage-plate group (44.88 ±â€Š6.54 vs. 54.43 ±â€Š14.71 min, P = 0.001). At all timepoints dysphagia rates were similar between the groups. Regression analysis confirmed preoperative SWAL-QOL and operative time were the only significant variables. PROMs were also similar between groups at all time points, except VAS neck at 6 months, which was lower in the plate-graft group (1.05 ±â€Š1.48 vs. 3.43 ±â€Š3.21, P = 0.007). CONCLUSION: Operative time and preoperative SWAL-QOL scores are predictive of dysphagia in single level ACDF. Zero profile devices had a significantly shorter operative time, and may provide a benefit in dysphagia rates in this regard. LEVEL OF EVIDENCE: 3.

Urinary N-Telopeptide Can Predict Pseudarthrosis After Anterior Cervical Decompression and Fusion: A Prospective Study.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To examine preoperative urinary cross-linked n-telopeptide (uNTx) and assess for association with fusion rates in patients undergoing single and multi-level anterior cervical decompression and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Although high rates of fusion have been reported for ACDF, the risk of pseudarthrosis remains substantial. An established marker of bone turnover, uNTx may prove useful as a predictor of fusion. METHODS: Patients undergoing primary ACDF with allograft/plating technique from 2015 to 2017 by a single surgeon were consecutively enrolled and preoperative uNTx was collected. Patients undergoing revision, with creatinine >1.2, and with improperly-collected uNTx were excluded. Demographics, laboratory values, and fusion status were assessed at 6 months, 1 year, and 2 years postoperatively. RESULTS: Of the 97 patients enrolled, 69 met inclusion criteria. Of included cases, 41%, 33%, 18%, and 8% underwent 1-, 2-, 3-, and 4-level ACDF, respectively. Overall, fusion rates were 37.3%, 70.9%, and 95.3% at 6 months, 1 year, and 2 years, respectively. uNTx was higher in the fusion group (31.1 vs. 22.2, P = 0.001) at 6 months and 1 year (30.0 vs. 21.0, P = 0.006), with no difference at 2 years. No differences were identified in the proportion of smokers, immunomodulatory agents, corpectomies, or fusion levels between groups. Multivariate regression analysis demonstrated that uNTx is an independent predictor of fusion (odds ratio, OR, 1.124, P = 0.003). Both groups experienced improvements in NDI and VAS neck pain at 6 months with no significant differences noted between groups. Of 16 patients with pseudarthrosis at 1 year, 2 underwent posterior cervical fusion for symptoms. CONCLUSION: Preoperative uNTx was greater in patients with successful ACDF fusion compared with patients with pseudarthrosis at 6 months and 1 year. A negative correlation was found between preoperative uNTx and motion on dynamic imaging. These results suggest that uNTx could serve to identify patients at risk for pseudarthrosis after ACDF. LEVEL OF EVIDENCE: 3.

Restoration of lumbar lordosis after minimally invasive transforaminal lumbar interbody fusion: a systematic review.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) is a well-accepted surgical technique for the treatment of degenerative spinal conditions and spinal deformity. The TLIF procedure can be performed open or using minimally invasive techniques. While several studies have found that minimally invasive TLIF (MI-TLIF) has advantages over open TLIF procedures with less blood loss, postoperative pain and hospital length of stay, opponents of the minimally invasive technique cite the lack of restoration of lumbar lordosis as a major drawback. With the increasing awareness of restoring sagittal alignment parameters in degenerative and deformity procedures, surgeons should understand the capabilities of different procedures to achieve surgical goals. To our knowledge, few studies have specifically studied the radiographic restoration of lumbar lordosis after MI-TLIF procedures. The purpose of this study was to perform a systematic review of the literature describing the sagittal lumbar radiographic parameter changes after MI-TLIF. METHODS: Following PRISMA guidelines, systematic review was performed. With the assistance of a medical librarian, a highly-sensitive search strategy formulated on 1/19/2018 utilized the following search terms: "minimally invasive procedures," "transforaminal lumbar interbody fusion," "lumbar interbody fusion," "diagnostic imaging," "radiographs," "radiography," "x-rays," "lordosis," "lumbar vertebrae," "treatment," "outcome," and "lumbosacral" using Boolean operators 'AND' and 'OR'. Three databases were searched (PubMed/Medline, Embase, and Cochrane Library). An online system (www.covidence.org) was used to standardize article review. All studies were independently analyzed by two investigators and discrepancies mitigated by a third reviewer. Study selection for each cycle was Yes/No/Maybe. Cycles were: (1) (Title/Abstract); (2) (Full Text); (3) (Extraction). Inclusion criteria were: (1) All study designs, (2) MI-TLIF procedures, (3) Reporting total lumbar lordosis (LL) and/or segmental lordosis (SL) pre- and postoperatively. Exclusion criteria were: (1) non MI-TLIF procedures (ALIF, XLIF, LLIF, conventional TLIF, OLIF), (2) No reported LL or SL. RESULTS: The search yielded 4,036 results with 836 duplicates leaving 3,200 studies for review. Cycle 1 eliminated 3,153 studies as irrelevant, thus, 47 were eligible for full-text review. Cycle 2 excluded 31 studies for No English full text (9), Oral/Poster (8), Wrong intervention/outcome (10), Duplicate listing (2), Full text not available (1), Literature review (1) resulting in 16 included studies. Study designs were: Randomized-controlled trial (3), Case series (6) and Retrospective (7). Mean # of subjects were 32.0 (range 8-95). Weighted-mean LL was 39.6°±9.2 (range 28-57) and postoperative LL was 45.0°±7.4 (range 36-67) with a LL post-pre difference of 5.2°±5.9 (range -7 to 15). Weighted-mean preoperative SL was 12.7°±4.3 (range 5-21) and postoperative SL was 15.0°±4.5 (range 5-22) with a SL post-pre difference of 2.1°±1.7 (range 0-8). CONCLUSIONS: The current literature on MI-TLIF and restoration of LL/SL is limited to 16 published studies, 44% of which are retrospective. The published evidence supporting LL and SL restoration with MI-TLIF is sparse with variable results. This systematic review demonstrates the need for future high-level studies to fully elucidate the capabilities of MI-TLIF procedures for restoring lumbar and segmental lordosis.

Overpowering the Previously Posterior Instrumented Cervical Spine With Cage-Assisted Anterior Cervical Discectomy and Fusion: A Cadaveric Study.

PURPOSE: Cervical spines previously posteriorly instrumented and fused with a kyphotic deformity represent a surgical challenge. Current treatment strategies include C7 pedicle subtraction osteotomy or a posterior-anterior-posterior approach, which carry the risk of significant complications. The objective of this study was to attempt to achieve lordosis with multiple anterior cervical discectomy and fusion (ACDF) cages to overpower the posterior instrumentation. METHODS: Four adult cadaveric specimens were selected and underwent C3-C7 posterior laminectomy with posterior instrumentation in a kyphotic alignment using a 3.5-mm titanium screw-rod system. Next, ACDF from C3 to C7 was performed with 15° lordotic cages to restore cervical lordosis. Posterior instrumentation was then inspected for failure. Fluoroscopic images were obtained to calculate total construct lordosis and change in segmental lordosis. CT scans were obtained after ACDF to assess for loosening, instrumentation failure, endplate damage, or impaction. Bone mineral density was calculated on CT scans. RESULTS: Age ranged from 59 to 82, and all specimens were male. No gross instrumentation failure was observed. Mean pre-ACDF lordosis between C3 and C7 was 0° (-5° to 5°). Post-ACDF lordosis increased to 37° (35°-38°). Mean segmental lordosis achieved with no endplate destruction was 13.1° (8°-17°). T scores for the cadavers were -0.5, -0.5, -3.2, and -5.1. Two levels of impaction were observed (12.5%). Failure of bone screw interface occurred in the cadaver, with a T score of -5.1 in the middle of the construct. CONCLUSION: Our study demonstrates the validity of overpowering posterior instrumentation through multiple level ACDF with lordotic cages. This may obviate the need to perform posterior-anterior-posterior procedures. LEVEL OF EVIDENCE: Level III.

Can Posterior Lumbar Instrumentation and Fusion Be Overpowered by Anterior Lumbar Fusion With Hyperlordotic Cages? A Cadaveric Study.

STUDY DESIGN: Technical report on cadavers. OBJECTIVE: To evaluate preliminary feasibility and safety of lumbar sagittal alignment correction with anterior hyperlordotic cages used to overpower previous posterior spinal instrumentation. METHODS: Hyperlordotic 30° anterior lumbar interbody fusion (ALIF) cages were inserted in collapsed L5-S1 disc space of 2 cadavers to overpower prior posterior L5-S1 pedicle screws and rod constructs. A distinct technique of opening up the disc space and creation of intersegmental lordosis was employed using a large endplate distractor and transforaminal lumbar interbody fusion (TLIF) paddle distractor. Assessment of increase in the intersegmental lordosis (ISL) was made using lateral fluoroscopic imaging. Postprocedural computed tomography (CT) scans were obtained to evaluate any failure of posterior instrumentation and to serve as a surrogate marker for bone quality. RESULTS: The 2 cadavers selected (from an available number of 10) were males: 82 and 84 years of age, respectively. Both had marked L5-S1 disc space collapse. The ISL achieved with hyperlordotic cages was 27.6° for the first cadaver (up from 4.9°) and 23.1° for the second one (up from 4.6°). No obvious screw-rod failure or cutout of instrumentation occurred. Postprocedure CT scans did not reveal any loosening of screws or cutout through endplates. Hounsfield unit values calculated on axial CT cuts were 73.50 (osteoporosis) and 80.70 (osteopenia) respectively for the 2 cadavers. CONCLUSION: Based on the results of the cadaveric experiment, overpowering of posterior instrumentation can be effectively achieved. Biomechanical and clinical studies are indicated to further evaluate the suitability and safety of this technique.

Overpowering posterior lumbar instrumentation and fusion with hyperlordotic anterior lumbar interbody cages followed by posterior revision: a preliminary feasibility study.

OBJECTIVE The authors' aim in this study was to evaluate whether sagittal plane correction can be obtained from the front by overpowering previous posterior instrumentation and/or fusion with hyperlordotic anterior lumbar interbody fusion (ALIF) cages in patients undergoing revision surgery for degenerative spinal conditions and/or spinal deformities. METHODS The authors report their experience with the application of hyperlordotic cages at 36 lumbar levels for ALIFs in a series of 20 patients who underwent revision spinal surgery at a single institution. Included patients underwent staged front-back procedures: ALIFs with hyperlordotic cages (12°, 20°, and 30°) followed by removal of posterior instrumentation and reinstrumentation from the back. Patients were divided into the following 2 groups depending on the extent of posterior instrumentation and fusion during the second stage: long constructs (≥ 6 levels with extension into thoracic spine and/or pelvis) and short constructs (< 6 levels). Preoperative and postoperative standing radiographs were evaluated to measure segmental lordosis (SL) along with standard sagittal parameters. Radiographic signs of pseudarthrosis at previously fused levels were also sought in all patients. RESULTS The average patient age was 54 years (range 30-66 years). The mean follow-up was 11.5 months (range 5-26 months). The mean SL achieved with 12°, 20°, and 30° cages was 13.1°, 19°, and 22.4°, respectively. The increase in postoperative SL at the respective surgically treated levels for 12°, 20°, and 30° cages that were used to overpower posterior instrumentation/fusion averaged 6.1° (p < 0.05), 12.5° (p < 0.05), and 17.7° (p < 0.05), respectively. No statistically significant difference was found in SL correction at levels in patients who had pseudarthrosis (n = 18) versus those who did not (n = 18). The mean overall lumbar lordosis increased from 44.3° to 59.8° (p < 0.05). In the long-construct group, the mean improvement in sagittal vertical axis was 85.5 mm (range 19-249.3 mm, p < 0.05). Endplate impaction/collapse was noted in 3 of 36 levels (8.3%). The anterior complication rate was 13.3%. No neurological complications or vascular injuries were observed. CONCLUSIONS ALIF in which hyperlordotic cages are used to overpower posterior spinal instrumentation and fusion can be expected to produce an increase in SL of a magnitude that is roughly half of the in-built cage lordotic angle. This technique may be particularly suited for lordosis correction from the front at lumbar levels that have pseudarthrosis from the previous posterior spinal fusion. Meticulous selection of levels for ALIF is crucial for safely and effectively performing this technique.

Anterior hyperlordotic cages: early experience and radiographic results.

OBJECTIVE The aim of this study was to evaluate the segmental correction obtained from 20° and 30° hyperlordotic cages (HLCs) used for anterior lumbar interbody fusion in staged anterior and posterior fusion in adults with degenerative spinal pathology and/or spinal deformities. METHODS The authors report a retrospective case series of 69 HLCs in 41 patients with adult degenerative spine disease and/or deformities who underwent staged anterior, followed by posterior, instrumentation and fusion. There were 29 females and 12 males with a mean age of 55 years (range 23-76 years). The average follow-up was 10 months (range 2-28 months). Radiographic measurements of segmental lordosis and standard sagittal parameters were obtained on pre- and postoperative radiographs. Implant subsidence was measured at the final postoperative follow-up. RESULTS For 30° HLCs, the mean segmental lordosis achieved was 29° (range 26°-34°), but in the presence of spondylolisthesis this was reduced to 19° (range 12°-21°) (p < 0.01). For 20° HLCs, the mean segmental lordosis achieved was 19° (range 16°-22°). The overall mean lumbar lordosis increased from 39° to 59° (p < 0.01). The mean sagittal vertical axis (SVA) reduced from 113 mm (range 38-320 mm) to 43 mm (range -13 to 112 mm). Six cages (9%) displayed a loss of segmental lordosis during follow-up. The mean loss of segmental lordosis was 4.5° (range 3°-10°). A total complication rate of 20% with a 4.1% transient neurological complication rate was observed. The mean blood loss per patient was 240 ml (range 50-900 ml). CONCLUSIONS HLCs provide a reliable and stable degree of segmental lordosis correction. A 30° HLC will produce correction of a similar magnitude to a pedicle subtraction osteotomy, but with a lower complication rate and less blood loss.

Vertebral body fracture after TLIF: a new complication.

BACKGROUND: The transforaminal posterior approach (TLIF) procedure was first described in 1982. Current literature indicates its equality in outcomes for fusion constructs as other anterior-posterior procedures. As a procedure becomes more popular and is more frequently performed the types and number of complications that occur increase. We report on a two case series that underwent TLIF. Both patients had satisfactory postoperative imaging, but presented later with coronal plane vertebral body fractures in the caudal vertebral body of the TLIF construct. We believe the complication may be related to: (a) unrecognized fracture of the endplate during cage impaction; (b) overloading the endplates by maximizing the lordosis achieved by using the reverse jackknife position on a Jackson table; (c) underlying mineral bone disease in patients. As the TLIF procedure increases in popularity, caution should be exercised to avoid the same potential complications. PURPOSE: To describe a potential complication with the TLIF procedure. STUDY DESIGN: Case report. PATIENT SAMPLE: 2. OUTCOME MEASURE: Revision surgery. METHODS: Case series. RESULTS: Caudal vertebral body fracture is a potential complication after TLIF. CONCLUSION: TLIF procedures can result in an unstable vertebral body fracture potentially necessitating revision decompression & stabilization. We recommend extra caution in patients with mineral bone disease, as technical errors can be magnified.

Medial approach for hindfoot arthrodesis with a valgus deformity.

BACKGROUND: Surgical correction of valgus deformity of the hindfoot has traditionally been via a lateral incision, often complicated by wound healing problems and sural nerve damage. Potential advantages of a medial approach especially for a valgus deformity include excellent wound healing, no risk of damage to the sural nerve and extensibility of the approach to include additional procedures such as navicular fusion or tendon transfer if indicated. MATERIALS AND METHODS: We present a retrospective review of 18 consecutive patients with valgus deformity of the hindfoot, all undergoing arthrodesis via a medial approach. Indications included osteoarthritis, tibialis posterior dysfucntion, post-traumatic arthritis and rheumatoid arthritis. RESULTS: All wounds healed by primary intention and there were no postoperative neurovascular complications. The mean preoperative subtalar valgus deformity was 32 (range, 12 to 49) degrees, which was improved to mean postoperative valgus deformity of 17 (range, 10 to 25) degrees. Fusion following the primary surgery was achieved in all but one of the patients (a heavy smoker and post-traumatic arthritis), with the mean time to fusion being 5.6 months. CONCLUSION: We provide further evidence to support previous documentation in the literature that the medial approach for the correction of hindfoot valgus deformity can be successfully used to achieve excellent exposure of the subtalar joint in order to correct the valgus deformity, avoiding the risks of wound healing and nerve damage associated with a lateral approach.