Polymethyl methacrylate augmentation and proximal junctional kyphosis in adult spinal deformity patients.

BACKGROUND: Proximal junctional kyphosis (PJK) is a complication following surgery for adult spinal deformity (ASD) possibly ameliorated by polymethyl methacrylate (PMMA) vertebroplasty of the upper instrumented vertebrae (UIV). This study quantifies PJK following surgical correction bridging the thoracolumbar junction ± PMMA vertebroplasty. METHODS: ASD patients from 2013 to 2020 were retrospectively reviewed and included with immediate postoperative radiographs and at least one follow-up radiograph. PMMA vertebroplasty at the UIV and UIV + 1 was performed at the surgeons' discretion. RESULTS: Of 102 patients, 56% received PMMA. PMMA patients were older (70 ± 8 vs. 66 ± 10, p = 0.021), more often female (89.3% vs. 68.2%, p = 0.005), and had more osteoporosis (26.8% vs. 9.1%, p = 0.013). 55.4% of PMMA patients developed PJK compared to 38.6% of controls (p = 0.097), and the rate of PJK development was not different between groups in univariate survival models. There was no difference in PJF (p > 0.084). Reoperation rates were 7.1% in PMMA versus 11.4% in controls (p = 0.501). In multivariable models, PJK development was not associated with the use of PMMA vertebroplasty (HR 0.77, 95% CI 0.38-1.60, p = 0.470), either when considered overall in the cohort or specifically in those with poor bone quality. PJK was significantly predicted by poor bone quality irrespective of PMMA use (HR 3.81, p < 0.001). CONCLUSIONS: In thoracolumbar fusions for adult spinal deformity, PMMA vertebroplasty was not associated with reduced PJK development, which was most highly associated with poor bone quality. Preoperative screening and management for osteoporosis is critical in achieving an optimal outcome for these complex operations. LEVEL OF EVIDENCE: 4, retrospective non-randomized case review.

Preoperative epidural steroid injections are not associated with increased rates of infection and dural tear in lumbar spine surgery.

PURPOSE: The study objectives were to use a large national claims data resource to examine rates of preoperative epidural steroid injections (ESI) in lumbar spine surgery and determine whether preoperative ESI or the timing of preoperative ESI is associated with rates of postoperative complications and reoperations. METHODS: A retrospective longitudinal analysis of patients undergoing lumbar spine surgery for disc herniation and/or spinal stenosis was undertaken using the MarketScan® databases from 2007-2015. Propensity-score matched cohorts were constructed to compare rates of complications and reoperations in patients with and without preoperative ESI. RESULTS: Within the year prior to surgery, 120,898 (46.4%) patients had a lumber ESI. The median time between ESI and surgery was 10 weeks. 23.1% of patients having preoperative ESI had more than one level injected, and 66.5% had more than one preoperative ESI treatment. Patients with chronic pain were considerably more likely to have an ESI prior to their surgery [OR 1.62 (1.54, 1.69), p < 0.001]. Patients having preoperative ESI within in close proximity to surgery did not have increased rates of infection, dural tear, neurological complications, or surgical complications; however, they did experience higher rates of reoperations and readmissions than those with no preoperative ESI (p < 0.001). CONCLUSION: Half of patients undergoing lumbar spine surgery for stenosis and/or herniation had a preoperative ESI. These were not associated with an increased risk for postoperative complications, even when the ESI was given in close proximity to surgery. Patients with preoperative ESI were more likely to have readmissions and reoperations following surgery.

Knee or Spine Surgery First? A Survey of Treatment Order for Patients With Concurrent Degenerative Knee and Lumbar Spinal Disorders.

BACKGROUND: Total knee arthroplasty (TKA) and lumbar spine surgery have been reported to affect the outcomes of each other. There is insufficient evidence to guide the choice of treatment order for patients with both disorders that are equally symptomatic. METHODS: Five clinical scenarios of concurrent, advanced, degenerative knee and lumbar spinal disorders were designed to survey surgeons' choices of treatment order and rationale. The spinal disorder was consistently degenerative lumbar spinal stenosis, but the knee conditions varied to include (1) osteoarthritis (OA) with varus deformity, (2) OA with valgus deformity, (3) rheumatoid arthritis with a severe flexion contracture, (4) OA without deformity, and (5) bilateral OA with windswept deformities. The survey was distributed to selected clinical members of the Knee Society and Scoliosis Research Society in North America. The surgeons' choices were compared among the 5 scenarios, and their comments were analyzed using text-mining. RESULTS: Responses were received from 42 of 74 (57%) knee arthroplasty surgeons and 55 of 100 (55%) spine surgeons. The percentages of knee arthroplasty surgeons recommending "TKA first" differed significantly among scenarios: 29%, 79%, 55%, 7%, and 81% for scenarios 1 through 5, respectively (P < .001). A similar pattern was noted for the spine surgeons. CONCLUSION: For patients with concurrent degenerative knee and lumbar spinal disorders, the severity and type of knee deformity influenced the preference of treatment order in both specialties. Severe valgus deformity and windswept deformities of the knee would drive the decision toward "TKA first."

Lateral femoral sliding osteotomy in total knee arthroplasty with valgus deformity greater than twenty degrees.

PURPOSE: Lateral femoral sliding osteotomy has been reported as an effective technique for total knee arthroplasty (TKA) with significant valgus deformity. This study aims to investigate its utility in TKA with valgus deformity greater than 20°, for which few studies have examined. METHODS: Consecutive TKA patients with valgus deformity treated with the sliding osteotomy at our institution were retrospectively studied. Constraint implants were not used. Radiological and clinical parameters at follow-ups were compared with those pre-operatively. Radiological parameters included the hip-knee-ankle angle (HKA), the anatomical lateral distal femoral angle (aLDFA), the anatomical lateral plateau ankle angle (aLPTA), and the angle between the femoral mechanical axis and transepicondylar line (femoral transepicondylar angle, FTEA) which was used to reflect concurrent extra-articular valgus and corresponding local alignment. Clinical outcome measures included the Knee Society Score and Functional Score. RESULTS: Twenty-five patients operated on between July 2011 and February 2017 were enrolled. The average follow-up time was 3.3 (1.5~7.9) years. The pre-operative HKA of 202.7 ± 2.3° (equivalent to valgus of 22.7 ± 2.3°) was reduced to 180.4 ± 2.3° at final follow-ups (P < 0.001). The aLFDA, aLPTA, and FTEA were all significantly improved, with the last one increased from 84.2 ± 1.8° to 89.6 ± 1.6° (t = - 11.35, P < 0.001). All clinical scores were significantly improved without major complications. CONCLUSIONS: Lateral femoral sliding osteotomy can be effective and safe for TKA with severe valgus deformity greater than 20°.

What Is the State of Quality Measurement in Spine Surgery?

BACKGROUND: Value-based healthcare models rely on quality measures to evaluate the efficacy of healthcare delivery and to identify areas for improvement. Quality measure research in other areas of health care has generally shown that there is a limited number of available quality measures and that those that exist disproportionately focus on processes as opposed to outcomes. The purpose of this study was to assess the current state of quality measures and candidate quality measures in spine surgery. QUESTIONS/PURPOSES: (1) How many quality measures and candidate quality measures are currently available? (2) According to Donabedian domains and National Quality Strategy (NQS) priorities, what aspects or domains of care do the present quality measures and candidate quality measures represent? METHODS: We systematically reviewed the National Quality Forum, the Agency for Healthcare Research and Quality, and the Physician Quality Reporting System for quality measures relevant to spine surgery. A systematic search for candidate quality measures was also performed using MEDLINE/PubMed and Embase as well as publications from the American Academy of Orthopaedic Surgeons, Congress of Neurological Surgeons, and the North American Spine Society. Clinical practice guidelines were included as candidate quality measures if their development was in accordance with Institute of Medicine criteria for the development of clinical practice guidelines, they were based on consistent clinical evidence including at least one Level I study, and they carried the strongest possible recommendation by the developing body. Quality measures and candidate quality measures were then pooled for analysis and categorized by clinical focus, NQS priority, and Donabedian domain. Our initial search yielded a total of 3940 articles, clinical practice guidelines, and quality measures, 74 of which met criteria for inclusion in this study. RESULTS: Of the 74 measures studied, 29 (39%) were quality measures and 45 (61%) were candidate quality measures. Fifty of 74 (68%) were specific to the care of the spine, and 24 of 74 (32%) were related to the general care of spine patients. The majority of the spine-specific measures were process measures (45 [90%]) and focused on the NQS priority of "Effective Clinical Care" (44 [88%]). The majority of the general care measures were also process measures (14 [58%]), the highest portion of which focused on the NQS priority of "Patient Safety" (10 [42%]). CONCLUSIONS: Given the large number of pathologies treated by spine surgeons, the limited number of available quality measures and candidate quality measures in spine surgery is inadequate to support the transition to a value-based care model. Additionally, current measures disproportionately focus on certain aspects or domains of care, which may hinder the ability to appropriately judge an episode of care, extract usable data, and improve quality. Physicians can steward the creation of meaningful quality measures by participating in clinical practice guideline development, assisting with the creation and submission of formal quality measures, and conducting the high-quality research on which effective guidelines and quality measures depend.

Patient Perceptions Correlate Weakly With Observed Patient Involvement in Decision-making in Orthopaedic Surgery.

BACKGROUND: Shared decision-making between patients and physicians involves educating the patient, providing options, eliciting patient preferences, and reaching agreement on a decision. There are different ways to measure shared decision-making, including patient involvement, but there is no consensus on the best approach. In other fields, there have been varying relationships between patient-perceived involvement and observed patient involvement in shared decision-making. The relationship between observed and patient-perceived patient involvement in decision-making has not been studied in orthopaedic surgery. QUESTIONS/PURPOSES: (1) Does patient-perceived involvement correlate with observed measurements of patient involvement in decision-making in orthopaedic surgery? (2) Are patient demographics associated with perceived and observed measurements of patient involvement in decision-making? METHODS: We performed a prospective, observational study to compare observed and perceived patient involvement in new patient consultations for eight orthopaedic surgeons in subspecialties including hand/upper extremity, total joint arthroplasty, spine, sports, trauma, foot and ankle, and tumor. We enrolled 117 English-literate patients 18 years or older over an enrollment period of 2 months. A member of the research team assessed observed patient involvement during a consultation with the Observing Patient Involvement in Decision-Making (OPTION) instrument (scaled 1-100 with higher scores representing greater involvement). After the consultation, we asked patients to complete a questionnaire with demographic information including age, sex, race, education, income, marital status, employment status, and injury type. Patients also completed the Perceived Involvement in Care Scale (PICS), which measures patient-perceived involvement (scaled 1-13 with higher scores representing greater involvement). Both instruments are validated in multiple studies in various specialties and the physicians were blinded to the instruments used. We assessed the correlation between observed and patient-perceived involvement as well as tested the association between patient demographics and patient involvement scores. RESULTS: There was weak correlation between observed involvement (OPTION) and patient-perceived involvement (PICS) (r = 0.37, p < 0.01) in decision-making (mean OPTION, 28.7, SD 7.7; mean PICS, 8.43, SD 2.3). We found a low degree of observed patient involvement despite a moderate to high degree of perceived involvement. No patient demographic factor had a significant association with patient involvement. CONCLUSIONS: Further work is needed to identify the best method for evaluating patient involvement in decision-making in the setting of discordance between observed and patient-perceived measurements. Knowing whether it is necessary for (1) actual observable patient involvement to occur; or (2) a patient to simply believe they are involved in their care can inform physicians on the best way to improve shared decision-making in their practice. LEVEL OF EVIDENCE: Level II, therapeutic study.

Ranges of Cervical Intervertebral Disc Deformation During an In Vivo Dynamic Flexion-Extension of the Neck.

While abnormal loading is widely believed to cause cervical spine disc diseases, in vivo cervical disc deformation during dynamic neck motion has not been well delineated. This study investigated the range of cervical disc deformation during an in vivo functional flexion-extension of the neck. Ten asymptomatic human subjects were tested using a combined dual fluoroscopic imaging system (DFIS) and magnetic resonance imaging (MRI)-based three-dimensional (3D) modeling technique. Overall disc deformation was determined using the changes of the space geometry between upper and lower endplates of each intervertebral segment (C3/4, C4/5, C5/6, and C6/7). Five points (anterior, center, posterior, left, and right) of each disc were analyzed to examine the disc deformation distributions. The data indicated that between the functional maximum flexion and extension of the neck, the anterior points of the discs experienced large changes of distraction/compression deformation and shear deformation. The higher level discs experienced higher ranges of disc deformation. No significant difference was found in deformation ranges at posterior points of all the discs. The data indicated that the range of disc deformation is disc level dependent and the anterior region experienced larger changes of deformation than the center and posterior regions, except for the C6/7 disc. The data obtained from this study could serve as baseline knowledge for the understanding of the cervical spine disc biomechanics and for investigation of the biomechanical etiology of disc diseases. These data could also provide insights for development of motion preservation surgeries for cervical spine.

The effect of short (2-weeks) versus long (6-weeks) post-operative restrictions following lumbar discectomy: a prospective randomized control trial.

PURPOSE: We sought to evaluate how short (2-week) versus long (6-week) post-operative restrictions following lumbar discectomy impacted outcomes and reherniation rates for a period up to 1 year following surgery. METHODS: This study included 108 patients undergoing index lumbar discectomy. Patients were randomized immediately following surgery. Outcomes included back and leg visual analog pain scales (VAS), Oswestry Disability Index (ODI), and reherniation rates at 2-weeks, 6-weeks, 3-months, and 1-year following surgery. Differences in reherniation rates were analyzed using Fisher's exact test. VAS and ODI scores were evaluated using Student's t test. RESULTS: Six patients (11%) in the 2-week restriction group had a reherniation event and four patients (7%) in the 6-week restriction group experienced a reherniation (p = 0.52). VAS back pain (p < 0.001), leg pain (p < 0.001), and ODI scores (p < 0.001) were significantly improved for both cohorts as compared to baseline at the 2-week time point and remained significantly improved through 1-year [VAS back (p < 0.001); VAS leg (p < 0.001); ODI (p < 0.001)]. No significant differences in ODI, VAS back, or VAS leg scores were detected at any of the time points between the 2- and 6-week restriction groups. CONCLUSIONS: The results of this randomized trial suggest equivalent clinical outcomes irrespective of the length of post-operative restriction. From a clinical perspective, if patients are deemed at low risk for a reherniation event they may be confidence that early return to activity at 2 weeks will not compromise outcomes and may not adversely impact the risk of reherniation. Level of Evidence II.

The influence of adjacent level disc disease on discectomy outcomes.

PURPOSE: The state of adjacent level discs and its impact on surgical outcomes following single-level lumbar discectomy have not been previously investigated. The purpose of the present study was to determine if a significant relationship exists between the degree of preoperative adjacent level disc degeneration and post-operative clinical outcomes following lumbar discectomy. METHODS: This study retrospectively used preoperative magnetic resonance imaging (MRI) and prospectively collected data from a randomized clinical trial at two tertiary-care academic hospitals. Patients who underwent a primary, single-level lumbar discectomy were included. Exclusion criteria included prior lumbar surgery. Outcome measures were the Modified Oswestry Disability Index (ODI) score and Visual Analog Scale (VAS) scores for back and leg pain. These were recorded at baseline and at 3 months, 1, and 2 years postoperatively. An independent reviewer graded adjacent level disc degeneration on all preoperative MRIs using the Pfirrmann grading scale. These data were then analyzed for correlation with each outcome measure. RESULTS: Forty-seven patients were included in the study. No statistically significant correlations were found when comparing preoperative 3-month or 1-year postoperative scores or change from baseline of any outcome measure between Pfirrmann grades. Only about half the patients had 2-year follow-up, but at that time point a statistically significant difference in back VAS scores was observed between Pfirrmann groups. No other significant differences were observed at that point. CONCLUSIONS: The degree of preoperative adjacent level degeneration does not significantly affect functional or pain relief outcomes following lumbar discectomy up to 1 year after surgery.

In-vivo T2-relaxation times of asymptomatic cervical intervertebral discs.

Limited research exists on T2-mapping techniques for cervical intervertebral discs and its potential clinical utility. The objective of this research was to investigate the in-vivo T2-relaxation times of cervical discs, including C2-C3 through C7-T1. Ten asymptomatic subjects were imaged using a 3.0 T MR scanner and a sagittal multi-slice multi-echo sequence. Using the mid-sagittal image, intervertebral discs were divided into five regions-of-interest (ROIs), centered along the mid-line of the disc. Average T2 relaxation time values were calculated for each ROI using a mono-exponential fit. Differences in T2 values between disc levels and across ROIs of the same disc were examined. For a given ROI, the results showed a trend of increasing relaxation times moving down the spinal column, particularly in the middle regions (ROIs 2, 3 and 4). The C6-C7 and C7-T1 discs had significantly greater T2 values compared to superior discs (discs between C2 and C6). The results also showed spatial homogeneity of T2 values in the C3-C4, C4-C5, and C5-C6 discs, while C2-C3, C6-C7, and C7-T1 showed significant differences between ROIs. The findings indicate there may be inherent differences in T2-relaxation time properties between different cervical discs. Clinical evaluations utilizing T2-mapping techniques in the cervical spine may need to be level-dependent.

Radiological evaluation of anterior lumbar fusion using PEEK cages with adjacent vertebral autograft in spinal deformity long fusion surgeries.

PURPOSE: The aim of this study was to evaluate the radiographic characteristics of polyetheretherketone (PEEK) cages packed with adjacent vertebral autograft material in lumbar anterior lumbar interbody fusion (ALIF) in spinal deformity long fusion surgeries. METHODS: This is a retrospective radiographic study. From April 2008 to April 2012, 40 patients (5 males and 35 females, mean age 67 ± 9 years) with coronal and/or sagittal spine deformities underwent staged corrective surgery combined with lumbar ALIF using PEEK cages at the L3-L4, L4-L5 or L5-S1 segment with posterior long (≥ 4 levels) instrumentation. The mean follow-up time was 27.5 months (13-49 months). We examined the interbody fusion rate and cage subsidence at 3 months postoperatively and final follow-up. Additionally, we evaluated the distance of cage migration at final follow-up and the improvement in lumbar lordosis. The rate of "collapse" of the adjacent vertebra where the autograft was harvested was assessed at the final follow-up. Finally, we examined the cage-related postoperative complications in this series. RESULTS: Solid interbody fusion was achieved in 96.4 % (81/84) of the levels at the final follow-up. A mild forward cage migration was observed, and the mean migration distance at final follow-up was 0.83 mm in L3/4, 0.36 mm in L4/5 and 0.55 mm in L5/S1. There was cage subsidence observed in 8.3 % (7/84) of the levels. In all patients, the PEEK cage maintained a significant increase in segmental lordosis at all postoperative visits. However, a mild reduction in segmental lordosis still occurred with time. The adjacent lumbar vertebral bodies where the autografts were harvested appeared to be intact in height radiologically at the final follow-up. There were no postoperative complications due to bone harvesting or cage insertion. Proximal junctional kyphosis was found in one patient who underwent a subsequent revision surgery. CONCLUSIONS: The use of lumbar ALIF with PEEK cages and adjacent vertebral autografts in spinal deformity long fusion surgeries is an effective and safe procedure. The allograft filler is safe and effective in maintaining the shape of harvested vertebrae. Additional long-term follow-up studies are needed to further justify its use.

Coronal Spinal Balance in Adult Spine Deformity Patients With Long Spinal Fusions: A Minimum 2- to 5-Year Follow-up Study.

STUDY DESIGN: This study was a retrospective one. OBJECTIVE: The objective of the study was to analyze the causes, prevalence of, and risk factors for coronal decompensation in long adult lumbar spinal instrumentation and fusion (from thoracic or upper lumbar spine) to L5 or S1. SUMMARY OF BACKGROUND DATA: Coronal and sagittal decompensation after long fusions for spinal deformities can affect outcomes negatively. There is no study reporting the natural history of coronal spinal balance after long spinal fusions. METHODS: A single-center retrospective review of data from 54 patients with spinal deformity was performed. Inclusion criteria were patients over 18 years with long fusions (>4 segments) to L5 or the pelvis who had full spine standing radiographs before surgery and up to 2-5 years postoperatively. Radiographic data included C7PL, magnitude of scoliotic curve, shoulder or pelvic asymmetry in the coronal plane, thoracic kyphosis, lumbar lordosis, and pelvic parameters (pelvic incidence, pelvic tilt, sacral slope). Coronal imbalance (CI) was considered if the C7PL was >4 cm lateral to the central sacral line, and sagittal imbalance (SI) was considered when the C7 plumbline was >4 cm anterior to the middle of the upper sacral plate. Paired t test, χ test, and repeated measures regression analysis using demographic data (age, sex, body mass index), operative (previous fusion, posterior only or anteroposterior fusion, iliac fixation or not, decompression or not, osteotomy or not) and postoperative (complications, use of bracing) data, and radiographic parameters (including SI) were performed. RESULTS: Patients showing CI equaled 11 (19.3%) preoperatively, remained 11 (19.3%) (4 of whom were new patients with CI) at 6 weeks postoperatively, and increased (P<0.001) to 18 (31.6%) (8 of them without initial CI) at 2-5 years follow-up. However, in terms of numeric distance of C7PL from the midsacrum, there was no statistically significant change (P>0.05) from preoperative to last follow-up. SI showed significant improvement (P<0.05) from preoperative to 6 weeks postoperative and no statistical significant change (P>0.05) from 6 weeks to 2-5 years postoperatively. Repeated measures regression analysis showed that the presence of osteoporosis and the combination of anterior approach surgery with a history of previous surgery were significant (P<0.05) factors predictive of changes in coronal balance. CONCLUSIONS: After surgical correction of spinal deformities, coronal spinal decompensation appears in an increased number of patients at last follow-up postoperatively but without significant differences in coronal plane C7PL during the postoperative period. Attention should be paid to patients with osteoporosis and those with a combination of previous same site posterior spine surgery and new anterior approach surgery for changes of coronal balance postoperatively.

Caudal vs transforaminal epidural steroid injections as short-term (6 months) pain relief in lumbar spinal stenosis patients with sciatica.

OBJECTIVE: The aim of this study is to evaluate prospectively the efficacy of caudal epidural steroid injection (CESI) and transforaminal epidural steroid injection (TFESI) in lumbar spinal stenosis patients with sciatic pain. DESIGN: Prospective clinical study. SETTING AND PATIENTS: Thirty-one patients (average age 62 years) from two hospitals, with single dermotomal distribution of sciatic pain due to spinal stenosis were included in the study. INTERVENTIONS: Patients underwent epidural steroid injections done by the same injectionist. Eleven patients from one hospital were included in the CESI group, while the TFESI group consisted of 20 comparable patients from the second site. OUTCOME MEASURES: Primary outcome measure was the complete relief or at least 50% reduction of pain (visual analog scale [VAS]) at 6 months postinjection. Secondary outcome measures were the improvement of function (of at least 15 points of Oswestry Disability Index [ODI]) at 6 months and the changes of VAS and ODI and at 2 weeks, at 3 months, and at 6 months postinjection. RESULTS: A significantly greater number of stenosis patients showed pain relief at 6 months postinjection with TFSI (90%) than with CESI (54.54%). All patients with TFSI showed improvement of function at 6 months while only three (27.27%) patients with caudal epidural improved functionally. Out of the total 31 patients, two patients from group A underwent a second CESI at 15 days postinjection and decompressive spine surgery between 3 and 6 months postinjection. CONCLUSIONS: The effectiveness of transforaminal steroid injection for the stenosis patients with sciatica was superior to caudal at 6 months postinjection.

Dynamic motion characteristics of the lower lumbar spine: implication to lumbar pathology and surgical treatment.

PURPOSE: Many studies have reported on the segmental motion range of the lumbar spine using various in vitro and in vivo experimental designs. However, the in vivo weightbearing dynamic motion characteristics of the L4-5 and L5-S1 motion segments are still not clearly described in literature. This study investigated in vivo motion of the lumbar spine during a weight-lifting activity. METHODS: Ten asymptomatic subjects (M/F: 5/5; age: 40-60 years) were recruited. The lumbar segment of each subject was MRI-scanned to construct 3D models of the L2-S1 vertebrae. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed a weight-lifting activity from a lumbar flexion position (45°) to maximal extension position. The 3D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral positions along the motion path. The relative translations and rotations of each motion segment were analyzed. RESULTS: All vertebral motion segments, L2-3, L3-4, L4-5 and L5-S1, rotated similarly during the lifting motion. L4-5 showed the largest anterior-posterior (AP) translation with 2.9 ± 1.5 mm and was significantly larger than L5-S1 (p < 0.05). L5-S1 showed the largest proximal-distal (PD) translation with 2.8 ± 0.9 mm and was significantly larger than all other motion segments (p < 0.05). CONCLUSIONS: The lower lumbar motion segments L4-5 and L5-S1 showed larger AP and PD translations, respectively, than the higher vertebral motion segments during the weight-lifting motion. The data provide insight into the physiological motion characteristics of the lumbar spine and potential mechanical mechanisms of lumbar disease development.

Radiographic analysis of PEEK cage and FRA in adult spinal deformity fused to sacrum.

STUDY DESIGN: Retrospective radiographic study. OBJECTIVE: To radiographically evaluate sagittal plane profile and fusion rates of polyetheretherketone (PEEK) cages versus femoral ring allografts (FRAs) in patients with adult spinal deformity fused to the sacrum. SUMMARY OF BACKGROUND DATA: FRAs have been widely used in various degenerative lumbar spine disorders and in adult deformity to achieve interbody fusions with promising results. PEEK cages have gained increasing popularity of late; however, there is little documentation to the radiographic comparisons between PEEK cages and FRAs used in patients with adult spine deformity treated with long fusions to the sacrum. METHODS: From March 2006 to February 2010, we analyzed 48 patients (mean age, 56.3±13.9 y) of 61 consecutive adult patients with global coronal and sagittal adult spine deformities who underwent first stage ALIF using PEEK cages or FRAs at L4-L5, L5-S1 segments followed by long (>6 levels) posterior instrumentation. PEEK cages and FRAs were used randomly according to surgeon's preference. Two independent observers retrospectively evaluated preoperative and postoperative disk height, foraminal height, segmental lordosis, and the interbody fusion rates at different postoperative intervals. RESULTS: Both PEEK cages and FRAs significantly (P<0.05) maintained disk space height at all follow-up times. PEEK cages maintained foraminal height and segmental lordosis, especially at L4-L5 better than FRAs at the final follow-up. At the final follow-up, PEEK cages achieved 94.9% of fusion rate, which was significantly (P<0.05) superior to FRA (84.2%), and PEEK cages were superior to FRAs in attaining earlier solid fusion. The Prolo functional scores of FRAs or/and PEEK cages were significantly improved at the final follow-up and did not show a significant difference between them. CONCLUSIONS: Both PEEK cages and FRAs can significantly increase disk space height and achieve similar clinical outcomes in treating adult spinal deformity fused to the sacrum. The radiographic results of PEEK cages were superior to FRAs in terms of an earlier solid fusion, and greater restoration of segmental lordosis.

Reliability of semi-automated spinal measurement software.

PURPOSE: In the treatment of patients with adult spinal deformity, analysis of spinopelvic balance is essential in clinical assessment and surgical planning. There is currently no gold standard for measurement, whether done by hand or with digital software. New semi-automated software exists that purports to increase efficiency, but its reliability is unknown in the literature. METHODS: Full spine X-rays were retrospectively reviewed from 25 adult patients seen between 2014 and 2017. Patients were included if they had > 5 cm of sagittal imbalance and radiographs of sufficient quality to perform balance measurements, without prior surgical spinal fusion and/or instrumentation. Spinopelvic parameters were measured in two radiographic programs: one with basic, non-spine-specific measurement tools (eUnity, Client Outlook, Waterloo, Canada); and a second with spine-specific semi-automated measurement tools (Sectra, Sectra AB, Linköping, Sweden). Balance parameters included SVA, PI, PT, and LL. Data were compared by examining inter-rater and inter-program reliability using interclass correlation coefficient (ICC). RESULTS: The subjects' mean age was 67.9 ± 13.8 years old, and 32% were male. The inter-program reliability was strong, with ICC values greater than 0.91 for each parameter. Similarly, there was strong inter-observer reliability with ICC values greater than 0.88. These results persisted on delayed repeat measurement (p < 0.001 for all measurements). CONCLUSION: There is excellent inter-observer and inter-program reliability between the basic PACS and semi-automated programs. These data demonstrate that the purported efficiency of semi-automated measurement programs does not come at the cost of measurement reliability.

Patient-level patterns in daily prescribed opioid dosage in single level lumbar fusion are associated with postoperative opioid dosage and adverse events: a retrospective analysis of claims data.

BACKGROUND: Patients undergoing lumbar spine surgery have high rates of preoperative opioid use, which is associated with inferior outcomes and higher risks for opioid dependency postoperatively. PURPOSE: Determine whether there are identifiable subgroups of patients that follow distinct patterns in pre- and postoperative opioid dosing. Examine how preoperative patterns in opioid dosing relate to postoperative opioid patterns, opioid cessation, and the risk for adverse events. STUDY DESIGN/SETTING: Retrospective analysis of an administrative claims database (MeritiveTM Marketscan® Research Databases 2007-2015). PATIENT SAMPLE: The 9,768 patients undergoing primary single level lumbar fusion. OUTCOME MEASURES: Primary: daily morphine milligram equivalent (MME) opioid dosing calculated from prescriptions dispensed for 1 year before and after surgery; secondary: 90-day all-cause readmission and complications, 90-day acute postoperative pain, 90-day and 1-year reoperation, surgical costs, length of stay, and discharge disposition. METHODS: Distinct patient subgroups defined by patterns of daily MME pre- and postoperatively were identified via group-based trajectory modeling. Associations between these groups and outcomes were assessed with multivariable logistic regression with risk adjustment for patient and surgical factors. RESULTS: Among primary single level lumbar fusion patients, 59.5% filled an opioid prescription in the 3 months preceding surgery, whereas 40.5% were opioid naïve (Naïve). Five distinct subgroups of daily MME were identified among those filling opioids preoperatively: (1) Naïve to 3m (21.2% of patients): no opioids until 3 months preoperatively, escalating to 15 MME/day; (2) Low to 3m (11.4%): very low or as needed dose until 3 months preoperatively, escalating to 15 MME/day; (3) 6m Rise (6.9%): no opioids until 6 months preoperatively, escalating to >30 MME/day; (4) Medium (9.8%): increased linearly from 10 to 25 MME/day across the year before surgery; (5) High (10.0%): increased linearly from 60 to >80 MME/day across the year before surgery. These five preoperative opioid groups were related to postoperative opioids filled in a dose-response manner. The two preoperative patient groups with chronic Medium to High-dose opioid dosing were associated with increased adverse events, including all-cause readmission, reoperation, and pneumonia, whereas a low baseline group with a large, earlier preoperative rise in opioid dosing (6m Rise) had increased encounters for acute postoperative pain. Postoperatively, only 9.5% of patients did not fill an opioid prescription. Five distinct postoperative subgroups were identified based on their patterns in daily MME: Two groups ceased filling opioids within the year following surgery (33.6% of patients), and three groups declined in opioid dosage following surgery but plateaued at low (0-5 MME/day, 29.1%), medium (10-15 MME/day, 12.0%), or high (70-75 MME/day), 13.1%) doses by 1 year. Patients within the higher preoperative opioid groups were more likely to belong to the postoperative groups that were unable to cease filling opioids. CONCLUSIONS: Identification of a patient's preoperative time trend in daily opioid use may provide significant prognostic value and help guide pain management and risk reduction efforts. LEVEL OF EVIDENCE: III.

Investigation of coupled bending of the lumbar spine during dynamic axial rotation of the body.

PURPOSE: Little is known about the coupled motions of the spine during functional dynamic motion of the body. This study investigated the in vivo characteristic motion patterns of the human lumbar spine during a dynamic axial rotation of the body. Specifically, the contribution of each motion segment to the lumbar axial rotation and the coupled bending of the vertebrae during the dynamic axial rotation of the body were analyzed. METHODS: Eight asymptomatic subjects (M/F, 7/1; age, 40-60 years) were recruited. The lumbar segment of each subject was MRI scanned for construction of 3D models of the vertebrae from L2 to S1. The lumbar spine was then imaged using a dual fluoroscopic system while the subject performed a dynamic axial rotation from maximal left to maximal right in a standing position. The 3D vertebral models and the fluoroscopic images were used to reproduce the in vivo vertebral motion. In this study, we analyzed the primary left-right axial rotation, the coupled left-right bending of each vertebral segment from L2 to S1 levels. RESULTS: The primary axial rotations of all segments (L2-S1) followed the direction of the body axial rotation. Contributions of each to the overall segment axial rotation were 6.7° ± 3.0° (27.9 %) for the L2-L3, 4.4° ± 1.2° (18.5 %) for the L3-L4, 6.4° ± 2.2° (26.7 %) for the L4-L5, and 6.4° ± 2.6° (27.0 %) for the L5-S1 vertebral motion segments. The upper segments of L2-L3 and L3-L4 demonstrated a coupled contralateral bending towards the opposite direction of the axial rotation, while the lower segments of L4-L5 and L5-S1 demonstrated a coupled ipsilateral bending motion towards the same direction of the axial rotation. Strong correlation between the primary axial rotation and the coupled bending was found at each vertebral level. We did not observe patterns of coupled flexion/extension rotation with the primary axial rotation. CONCLUSIONS: This study demonstrated that a dynamic lumbar axial rotation coupling with lateral bendings is segment-dependent and can create a coordinated dynamic coupling to maintain the global dynamic balance of the body. The results could improve our understanding of the normal physiologic lumbar axial rotation and to establish guidelines for diagnosing pathological lumbar motion.

Motion characteristics of the lumbar spinous processes with degenerative disc disease and degenerative spondylolisthesis.

OBJECTIVE: Recently, interspinous process devices have attracted much attention since they can be implanted between the lumbar spinous processes (LSP) of patients with degenerative disc disease (DDD) and degenerative spondylolisthesis (DLS) using a minimally invasive manner. However, the motion characters of the LSP in the DLS and DDD patients have not been reported. This study is aimed at investigating the kinematics of the lumbar spinous processes in patients with DLS and DDD. METHODS: Ten patients with DDD at L4-S1 and ten patients with DLS at L4-L5 were studied. The positions of the vertebrae (L2-L5) at supine, standing, 45° trunk flexion, and maximal extension positions were determined using MRI-based models and dual fluoroscopic images. The shortest ISP distances were measured and compared with those of healthy subjects that have been previously reported. RESULTS: The shortest distance of the interspinous processes (ISP) gradually decreased from healthy subjects to DDD and to DLS patients when measured in the supine, standing, and extension positions. During supine-standing and flexion-extension activities, the changes in the shortest ISP distances in DDD patients were 2 ± 1.2 and 4.8 ± 2.1 mm at L4-L5; in DLS patients they were 0.5 ± 0.4 and 2.8 ± 1.7 mm at L4-L5, respectively. The range of motion is increased in DDD patients but decreased in DLS patients when compared with those of the healthy subjects. No significantly different changes were detected at L2-L3 and L3-L4 levels. CONCLUSION: At the involved level, the hypermobility of the LSP was seen in DDD and hypomobility of the LSP in DLS patients. The data may be instrumental for improving ISP surgeries that are aimed at reducing post-operative complications such as bony fracture and device dislocations.

Motion characteristics of the vertebral segments with lumbar degenerative spondylolisthesis in elderly patients.

OBJECTIVE: Although some studies have reported on the kinematics of the lumbar segments with degenerative spondylolisthesis (DS), few data have been reported on the in vivo 6 degree-of-freedom kinematics of different anatomical structures of the diseased levels under physiological loading conditions. This research is to study the in vivo motion characteristics of the lumbar vertebral segments with L4 DS during weight-bearing activities. METHODS: Nine asymptomatic volunteers (mean age 54.4) and 9 patients with L4 DS (mean age 73.4) were included. Vertebral kinematics was obtained using a combined MRI/CT and dual fluoroscopic imaging technique. During functional postures (supine, standing upright, flexion, and extension), disc heights, vertebral motion patterns and instability were compared between the two groups. RESULTS: Although anterior disc heights were smaller in the DS group than in the normal group, the differences were only significant at standing upright. Posterior disc heights were significantly smaller in DS group than in the normal group under all postures. Different vertebral motion patterns were observed in the DS group, especially in the left-right and cranial-caudal directions during flexion and extension of the body. However, the range of motions of the both groups were much less than the reported criteria of lumbar spinal instability. CONCLUSION: The study showed that lumbar vertebra with DS has disordered motion patterns. DS did not necessary result in vertebral instability. A restabilization process may have occurred and surgical treatment should be planned accordingly.