Lawrence G Lenke

University of Utah, Salt Lake City, Utah, United States

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Publications (408)875.68 Total impact

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    ABSTRACT: Retrospective matched-cohort comparative study.
    Spine 10/2014; 39(22):1899-1904. · 2.16 Impact Factor
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    ABSTRACT: Study Design Retrospective review of multicenter data set with adolescent idiopathic scoliosis (AIS) patients with at least 2 years of follow-up after posterior spinal instrumentation and fusion (PSIF). Objectives The purpose of this study is to investigate risk factors for coronal decompensation 2 years after PSIF for AIS. Summary of Background Data Coronal decompensation is a potential complication of spinal instrumentation for AIS. This can result in problems requiring revision surgery. Methods Demographic, clinical, and radiographic measures were reviewed on 890 identified patients. Coronal decompensation was defined as a change farther away from midline from 6 weeks postoperatively to 2 years in any one of the following radiographic parameters: change in coronal balance >2 cm; change in coronal position of the lowest instrumented vertebra (LIV) >2 cm; change in thoracic trunk shift >2 cm; or change in LIV tilt angle >10°. Patients with decompensation were compared to those without. The relationship between the LIV and lowest end vertebra (LEV) was examined as an independent variable. Results Two years postoperation, 6.4% (57/890) of patients exhibited coronal decompensation. Multivariate regression revealed that decompensated patients were twice as likely to be male, have lower preoperative Risser score, and lower percentage major curve correction. The relationship between the LIV and LEV as well as quality of life surveys were not significantly different between decompensated and nondecompensated patients at 2 years. Conclusions Two years after PSIF, 6.4% of patients with AIS exhibit radiographic coronal decompensation. Although this study did not demonstrate a significant association between the relationship of LIV and LEV and decompensation 2 years postoperation, results of this study indicate that skeletal immaturity, male gender, and less correction of the major curve may be related to higher rates of coronal decompensation.
    Spine Deformity. 09/2014; 2(5):380–385.
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    ABSTRACT: Study Design Consensus-based creation of a checklist and guideline. Objective To develop a consensus-based checklist to guide surgeon responses to intraoperative neuromonitoring (IONM) changes in patients with a stable spine and to develop a consensus-based best practice guideline for IONM practice in the United States. Summary of Background Data Studies show that checklists enhance surgical team responses to crisis situations and improve patient outcomes. Currently, no widely accepted guidelines exist for the response to IONM changes in spine deformity surgery. Methods After a literature review of risk factors and recommendations for responding to IONM changes, 4 surveys were administered to 21 experienced spine surgeons and 1 neurologist experienced in IONM. Areas of equipoise were identified and the nominal group process was used to determine items to be included in the checklist. The authors reevaluated and modified the checklist at 3 face-to-face meetings over 12 months, including a period of clinical validation using a modified Delphi process. The group was also surveyed on current IONM practices at their institutions. This information and existing IONM position statements were used to create the IONM best practice guideline. Results Consensus was reached for the creation of 5 checklist headings containing 26 items to consider in the response to IONM changes. Consensus was reached on 5 statements for inclusion in the best practice guideline; the final guideline promotes a team approach and makes recommendations aimed at decreasing variability in neuromonitoring practices. Conclusions The final products represent the consensus of a group of expert spine surgeons. The checklist includes the most important and high-yield items to consider when responding to IONM changes in patients with a stable spine, whereas the IONM guideline represents the group consensus on items that should be considered best practice among IONM teams with the appropriate resources.
    Spine Deformity. 09/2014; 2(5):333–339.
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    ABSTRACT: Study Design Retrospective. Objectives The authors hypothesized that cervical lordosis (CL) would decrease with aging and increasing degeneration. Summary of Background Data It is theorized that with age and degeneration, the cervical spine loses lordosis and becomes progressively more kyphotic; however, no studies support these conclusions in patients with various spinal deformities. Methods The authors performed a radiographic analysis of asymptomatic adults (referring to their cervical spine) of varying ages, with differing forms of spinal deformity to the thoracic/lumbar spine to see how cervical lordosis changes with increasing age. A total of 104 total spine EOS X-rays of adult (aged >18 years) spinal deformity patients without documented neck pain, prior neck surgery, or cervical deformity were reviewed. The researchers only reviewed EOS X-rays because they allow complete visualization from occiput to feet. Cervical lordosis, standard Cobb measurements, sagittal balance parameters, and cervical degeneration were quantified radiographically by the method previously described by Gore et al. Statistical analysis was performed with 1-way analysis of variance to compare significant differences between groups aged <40, 40–60 and >60 years as well as changes in sagittal balance. A p-value < .05 was considered significant. Results Average CL actually increased with increasing age (10.3 ± 14.7, 15.4 ± 15.1, and 23.3 ± 1.6.7 for age < 40, 40–60, and > 60 years, respectively; p < .05). Average cervical degeneration score increased at all disc space levels from C2 to C7 across age groups (0.7 ± 1.2, 9.9 ± 69, and 16.3 ± 8.9 for age <40, 40–60, and >60 years, respectively; p < .01), with the highest degeneration at the C5–6 and C6–7 disc spaces (3.7 ± 3.3 and 3.2 ± 2.9, respectively; p < .01). This increase did not correlate with the increase in CL seen with aging (r = 0.02; p = .84). Conclusions Cervical lordosis increased with aging in adult spinal deformity patients. There was no relationship between cervical degeneration and lordosis despite the strong relationship seen between increasing CL in older age groups.
    Spine Deformity. 09/2014; 2(5):410–414.
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    ABSTRACT: Study Design Retrospective comparative study. Objectives To compare correction rates and complications of revision versus primary patients undergoing vertebral column resection (VCR). Summary of Background Data Although an all-posterior VCR has obviated the need for a circumferential approach, it is technically demanding, especially in a revision setting. Methods Between 2002 and 2009, 55 revision patients underwent a posterior-only VCR. Diagnoses included severe scoliosis (n = 3), kyphoscoliosis (KS) (n = 29), global kyphosis (GK) (n = 13), and angular kyphosis (AK) (n = 10). Radiographic findings and complications were compared with 38 primary patients who underwent a VCR during the same period. All patients had a minimum 2-year follow-up (range, 2–6 years). Results The mean number of VCR levels were 1.6 in revision versus 1.2 in primary cases (p = .005). In the severe scoliosis and KS groups, major coronal curve correction was 48% in revision versus 63% in primary cases (p = .001). In the KS, GK, and AK groups, the major sagittal curve correction was 52% in revision versus 57% in primary cases (p = .27). Preoperative (p = .015) and postoperative (p = .002) sagittal imbalance was significantly greater in the revision group. There were no spinal cord–related complications, but 7 revision (13%) and 3 primary (8%) patients temporarily lost neuromonitoring data or failed wakeup tests; however, none had a permanent neurological deficit. Six revision patients (11%) required further revision surgery due to implant failure (3), progressive sagittal or coronal imbalance (2), and delayed deep wound infection (1) versus only 1 primary patient (3%) due to increased coronal imbalance. Preoperative and postoperative Scoliosis Research Society scores were not significantly different between groups. Conclusions Vertebral column resections in revision patients may be more technically demanding than in primary patients but can be performed safely in conjunction with intraoperative spinal cord monitoring. Revision and primary patients undergoing a VCR showed improved clinical outcomes.
    Spine Deformity. 09/2014; 2(5):350–357.
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    ABSTRACT: Study Design. Retrospective review of pedicle subtraction osteotomy (PSO) cases.Objective. To report our results, radiographic and clinical outcomes at a minimum 5 years after revision surgery for pseudarthrosis following a PSO.Summary of Background Data. To our knowledge, there is no report on the results of revision surgery for pseudarthrosis following a PSO.Methods. Eighteen consecutive patients with pseudarthrosis following pedicle subtraction osteotomy (16 women/2 men, average age at surgery, 49.8 years) treated with revision surgery at one institution were analyzed (average follow-up, 6.5 years; range, 5-12 years). Radiographic and clinical outcomes analysis was performed.Results. Sagittal vertical axis (SVA) and lumbar lordosis (LL) improved significantly after revision surgery (SVA, P = 0.000; LL, P = 0.024) and were maintained until ultimate post-revision followup (SVA, P = 0.170; LL, P = 0.729). Proximal junctional angle (P = 0.828), thoracic kyphosis (P = 0.828), and PSO angle (P = 0.717) achieved by the primary surgery were also maintained until ultimate post-revision. We increased the number of rods and/or changed them to 6.35 mm diameter in all patients. There were significant improvements post-revision in Oswestry (ODI) (45 vs. 37.9, P = 0.041) and Scoliosis Research Society (SRS) pain subscale (2.6 vs. 3.1, P = 0.047), but not in SRS total score or other subscales. Pelvic incidence > 60° demonstrated a trend toward poorer ODI and SRS scores (P > 0.05), but there were no significant differences between SVA ≤ or >11 cm.Conclusions. Revision surgery for pseudarthrosis following pedicle subtraction osteotomy can provide acceptable radiographic and clinical outcomes at a minimum 5 years post-revision. Successful surgical outcomes may be achieved by using an increased number or size of implants and ample bone graft for complete fusion after revision surgery.
    Spine 07/2014; · 2.16 Impact Factor
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    ABSTRACT: Study Design. Anatomic study.Objective. To determine whether the thoracic spinal canal diameter decreases when the pedicle is allowed to expand with increasing screw diameter. To observe whether osseous breach occurs medially or laterally.Summary of Background Data. Insertion of a pedicle screw that is larger in diameter than that of the native pedicle has been shown to expand the pedicle and increase biomechanical fixation strength. With this technique, there is concern for medial expansion of the pedicle causing decrease in spinal canal diameter, especially in the concavity of scoliosis, resulting in spinal cord compression. Also, large pedicle screws that are inserted correctly may still cause undetected medial bony breach during surgery.Methods. 162 pedicles from 81 thoracic vertebrae (T1-T12) of 7 fresh-frozen adult cadavers were analyzed. After undertapping the pedicle by 1 mm, pedicle screws were inserted in increasing diameter (range, 4.0 mm - 9.5 mm) bilaterally until there was an osseous breach in the pedicle. 938 screws were used in total. Transverse spinal canal diameter and pedicle circumference were measured (in mm) before and after each pedicle screw placement. Photographs and fluoroscopic images of representative specimens were taken for visual assessment.Results. The average transverse spinal canal diameter was 17.7 mm. The average transverse canal diameter with the largest screw inserted before bony breach was detected was 17.6 mm (p = 0.92). The average diameter of the largest screw inserted before breach was 6.9 mm. Pedicle circumference increased from 41.8 mm before screw placement to 43.4 mm at maximal expansion before bony breach with the next sized screw. Twenty-eight pedicles did not break with 9.5 mm-diameter screws. There were 133 lateral and 1 medial breaches.Conclusion. Increasing pedicle screw size caused pedicle expansion laterally but did not significantly alter transverse spinal canal dimensions. When there was an osseous breach, most were lateral (99.3%).
    Spine 07/2014; · 2.16 Impact Factor
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    ABSTRACT: Retrospective review of prospectively collected data.
    Spine 07/2014; 39(15):1190-1195. · 2.16 Impact Factor
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    ABSTRACT: The surgical management of adolescent idiopathic scoliosis (AIS) has seen many developments in the last two decades. Little high-level evidence is available to support these changes and guide treatment. This study aimed to identify optimal operative care for adolescents with AIS curves between 40° and 90° Cobb angle.
    06/2014;
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    ABSTRACT: Study Design. Retrospective case-seriesObjective. Share our institutional experience with spinal reconstruction for deformity correction in patients with a history of poliomyelitis.Background Data. Polio and post-polio syndrome are not uncommonly related to a paralytic spinal deformity. Limited modern data exists regarding outcomes and complications following spinal reconstruction in this population.Methods. A clinical database was reviewed for patients undergoing spinal reconstruction for polio-associated spinal deformity at our institution from 1985 to 2012. Relevant demographic, medical, surgical and postoperative information were collected from medical records and analyzed. Preoperative and last follow-up SRS-22 scores were recorded.Results. A total of 22 patients with polio who underwent surgical deformity correction were identified. Mean age was 49 years (Range, 12-74), and 15 patients (68%) were female. Preoperative motor deficit was present in 14/22 (64%). All patients underwent instrumented spinal fusion (Mean 13 vertebral levels, Range, 3-18). Ten (10/22, 45%) patients developed major complications, and four patients (4/22, 18%) developed new postoperative neurological deficits. Neurological monitoring yielded a 13% false negative rate. At 2-year follow-up (20/22), patients maintained an average coronal correction of 25 degrees (33%, p = 0.001) and sagittal correction of 25 degrees (34%, p = 0.003). Minimum 2-year follow-up data were available for 11/22 (50%) of patients. At an average of 72 months of follow-up (Range, 28 - 134 months), the mean SRS22 pain subscore improved from a mean of 2.75 to 3.6 (p = 0.012); self-image from 2.8 to 3.7 (p = 0.041); function from 3.1 to 3.8 (p = 0.036); satisfaction from 2.1 to 3.9 (p = 0.08); mental health from 3.7 to 4.5 (p = 0.115).Conclusion. Spine reconstruction for poliomyelitis-associated deformity was associated with high complication rates (54%) and sometimes unreliable neurologic monitoring data. Despite this, patients undergoing spine reconstructions had significantly improved outcomes scores. These data may help surgeons appropriately counsel this complicated patient population.
    Spine 05/2014; · 2.16 Impact Factor
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    ABSTRACT: Object The goal in this study was to evaluate the risk factors for complications, including new neurological deficits, in the largest cohort of patients with adult spinal deformity to date. Methods The Scoli-RISK-1 inclusion criteria were used to identify eligible patients from 5 centers who were treated between June 1, 2009, and June 1, 2011. Records were reviewed for patient demographic information, surgical data, and reports of perioperative complications. Neurological deficits were recorded as preexisting or as new deficits. Patients who underwent 3-column osteotomies (3COs) were compared with those who did not (posterior spinal fusion [PSF]). Between-group comparisons were performed using independent samples t-tests and chi-square analyses. Results Two hundred seven patients were identified-75 who underwent PSF and 132 treated with 3CO. In the latter group, patients were older (58.9 vs 49.4 years, p < 0.001), had a higher body mass index (29.0 vs 25.8, p = 0.029), smaller preoperative coronal Cobb measurements (33.8° vs 56.4°, p < 0.001), more preoperative sagittal malalignment (11.7 cm vs 5.4 cm, p < 0.001), and similar sagittal Cobb measurements (45.8° vs 57.7°, p = 0.113). Operating times were similar (393 vs 423 minutes, p = 0.130), although patients in the 3CO group sustained higher estimated blood loss (2120 vs 1700 ml, p = 0.066). Rates of new neurological deficits were similar (PSF: 6.7% vs 3CO: 9.9%, p = 0.389), and rates of any perioperative medical complication were similar (PSF: 46.7% vs 3CO: 50.8%, p = 0.571). Patients who underwent vertebral column resection (VCR) were more likely to sustain medical complications than those treated with pedicle subtraction osteotomy (73.7% vs 46.9%, p = 0.031), although new neurological deficits were similar (15.8% vs 8.8%, p = 0.348). Regression analysis did not reveal significant predictors of neurological injury or complication from collected data. Conclusions Despite higher estimated blood loss, rates of all complications (49.3%) and new neurological deficits (8.7%) did not vary for patients who underwent complex reconstruction, whether or not a 3CO was performed. Patients who underwent VCR sustained more medical complications without an increase in new neurological deficits. Prospective studies of patient factors, provider factors, and refined surgical data are needed to define and optimize risk factors for complication and neurological deficits.
    Neurosurgical FOCUS 05/2014; 36(5):E17. · 2.49 Impact Factor
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    ABSTRACT: Object Minimally invasive surgery (MIS) is an alternative to open deformity surgery for the treatment of patients with adult spinal deformity. However, at this time MIS techniques are not as versatile as open deformity techniques, and MIS techniques have been reported to result in suboptimal sagittal plane correction or pseudarthrosis when used for severe deformities. The minimally invasive spinal deformity surgery (MISDEF) algorithm was created to provide a framework for rational decision making for surgeons who are considering MIS versus open spine surgery. Methods A team of experienced spinal deformity surgeons developed the MISDEF algorithm that incorporates a patient's preoperative radiographic parameters and leads to one of 3 general plans ranging from MIS direct or indirect decompression to open deformity surgery with osteotomies. The authors surveyed fellowship-trained spine surgeons experienced with spinal deformity surgery to validate the algorithm using a set of 20 cases to establish interobserver reliability. They then resurveyed the same surgeons 2 months later with the same cases presented in a different sequence to establish intraobserver reliability. Responses were collected and tabulated. Fleiss' analysis was performed using MATLAB software. Results Over a 3-month period, 11 surgeons completed the surveys. Responses for MISDEF algorithm case review demonstrated an interobserver kappa of 0.58 for the first round of surveys and an interobserver kappa of 0.69 for the second round of surveys, consistent with substantial agreement. In at least 10 cases there was perfect agreement between the reviewing surgeons. The mean intraobserver kappa for the 2 surveys was 0.86 ± 0.15 (± SD) and ranged from 0.62 to 1. Conclusions The use of the MISDEF algorithm provides consistent and straightforward guidance for surgeons who are considering either an MIS or an open approach for the treatment of patients with adult spinal deformity. The MISDEF algorithm was found to have substantial inter- and intraobserver agreement. Although further studies are needed, the application of this algorithm could provide a platform for surgeons to achieve the desired goals of surgery.
    Neurosurgical FOCUS 05/2014; 36(5):E6. · 2.49 Impact Factor
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    ABSTRACT: Study Design. Retrospective review of prospective database.Objective. To investigate the long-term results following extension of previous long spine fusions to the sacrum.Summary of Background Data. Long spine fusions not involving the sacrum may be complicated by distal degeneration and require subsequent extension to the sacrum. The clinical and radiographic outcomes following such revision remain unknown.Methods. Patients who had extension of a long fusion (≥ 5 levels with a thoracic level at the cranial end) to the sacrum between 2002-2007 at a single institution were analyzed. ODI and SRS scores and/or radiographic parameters were assessed at baseline, 6 weeks and 1, 2, 3 and/or 5 years postoperatively (PO) and complications were recorded.Results. There were 74 patients included with an average age of 49yrs (range: 19-76yrs) and average clinical follow-up of 4.5yrs (range 3mos to 10yrs, 82% >2yrs PO). All had degeneration distal to prior fusions and 72% (n = 53) had fixed sagittal imbalance. Sagittal alignment improved at all PO time points from baseline (mean 78mm), but worsened between 1yr (mean 21mm) and 5yrs PO (mean 44mm, p = 0.01). Major surgical complications occurred in 30% (n = 22) and there were 17 major reoperations in 15 patients (20%). Significant improvements (p<0.05) in ODI and all SRS domain scores were found at each PO time point with no deterioration from 1 to 5yrs PO. Mean outcome scores at 5yrs PO were similar in groups with major surgical complications vs. without and with major reoperation vs. without.Conclusion. Extension of long fusions to the sacrum resulted in significant and sustained improvements in ODI and SRS scores and alignment over 5yrs PO compared to baseline. Major surgical complications occurred in 30% and reoperations were performed in 20%, but outcome scores following treatment were similar to those without complications or reoperations.
    Spine 04/2014; · 2.16 Impact Factor
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    ABSTRACT: The role of preoperative narcotic use and its influence on outcomes following spinal deformity surgery is unknown. It is important to determine what patient factors and co-morbidities can affect the success of spinal deformity surgery, a challenging surgery with high rates of complications at baseline. Evaluate if preoperative narcotic use persists following spinal deformity surgery, and whether the outcomes are adversely affected by preoperative narcotic use. Retrospective evaluation of prospectively collected data PATIENT SAMPLE: 253 adult patients (230 females/23 males) undergoing primary spinal deformity surgery were enrolled from 2000 to 2009. Pre-operative and post-operative narcotic use. Changes in Oswestry Disability Index (ODI), Scoliosis Research Society (SRS) pain and SRS total score. Preoperative, 2-year postoperative and latest follow-up pain medication use were collected along with ODI, SRS pain and SRS scores. Preoperative insurance status, surgical and hospitalization demographics and complications were collected. All patients had a minimum 2-year follow-up (average, 47.4 months). 168 patients (NoNarc) were taking no pain meds/NSAIDs only preoperative. 85 patients (Narc) were taking mild/moderate/heavy narcotics prior to surgery. The average age was 48.2 for the NoNarc versus 53.6 for the Narc group (p<0.005). There were significantly more patients with degenerative than adult scoliosis in the Narc group (47 vs. 28, p<0.001; mild 19 vs. 24, p<0.02; moderate 6 vs. 14, p<0.0003; heavy 3 vs. 10, p<0.0002). Insurance status (private/Medicare/Medicaid) was similar between the groups (p=0.39). At latest follow-up, 137/156 (88%) prior NoNarc patients were still not taking narcotics while 48/79 (61%) prior Narc patients were now off narcotics (p<0.001). Significant postoperative improvements were seen in Narc versus NoNarc with regard to ODI (26-15 vs. 44-30.3, p<0.001), SRS pain (3.36-3.9 vs. 2.3-3.38, p<0.001) and overall SRS outcomes scores (3.36-4 vs. 2.78-3.68, p<0.001). A comparison of change in outcomes scores between the two groups showed a higher improvement in SRS pain scores for the Narc versus NoNarc group (p<0.001). In adults with degenerative scoliosis taking narcotics a significant decrease in pain medication use was noted following surgery. All outcome scores significantly improved postoperative in both groups. However, the Narc group had significantly greater improvements in SRS pain scores versus the NoNarc group.
    The spine journal: official journal of the North American Spine Society 04/2014; · 2.90 Impact Factor
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    ABSTRACT: Retrospective review of prospective database. To investigate long-term results after 3-column osteotomies (3-CO). Short-term studies have noted improved outcomes and alignment after 3-CO, but there is a paucity of long-term studies with a large group of patients. An analysis of 126 patients who underwent a 3-CO (pedicle subtraction osteotomy [N = 101]/vertebral column resection [N = 25]) with minimum 5-year follow-up was performed at a single institution. The mean age was 48 years (range, 8-79 yr) and average follow-up was for 7 years (range, 5-14 yr). Oswestry Disability Index and Scoliosis Research Society (SRS) scores and radiographical parameters were assessed at baseline, 6 weeks, and 1, 2, 3, and/or 5 years postoperatively and complications were recorded. Sagittal alignment improved at all postoperative time points from baseline (mean, 117 mm), but diminished from 6 weeks (mean, 24 mm) to 5 years (mean, 41 mm; P = 0.03). Average coronal alignment was improved from baseline (27 mm) at 6 weeks (18 mm; P = 0.003) and 5 years postoperatively (19 mm; P = 0.007), with no deterioration between 6 weeks and 5 years postoperatively (P = 0.9). Major surgical complications occurred in 36% (n = 45) and major repeat surgery was performed in 28% (n = 35). Significant improvements (P < 0.05) in Oswestry Disability Index and all SRS domain scores were found at each time point. All mean outcome scores at 5 years postoperatively exceeded minimal clinically important difference thresholds except the SRS function domain. Improvement in outcomes at 5 years postoperatively was similar in groups with major surgical complications versus those without and in those with reoperation versus those without. This study of 126 patients undergoing 3-CO found significant and sustained improvements in Oswestry Disability Index and SRS scores and sagittal alignment at a minimum 5 years postoperatively. This demonstrates the durability of these complex spinal reconstructions, even surprisingly in those patients having a major complication and/or revision surgery.Level of Evidence: 4.
    Spine 03/2014; 39(5):424-32. · 2.16 Impact Factor
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    ABSTRACT: A previous biomechanical study using adult thoracic vertebrae (both normal and osteoporotic bone density) demonstrated the deleterious effect of the pedicle screw hubbing technique. Pedicle screw "hubbing" involves seating and engaging the ventral aspect of the screw head onto the dorsal lamina cortex. This technique is postulated to provide a load-sharing effect by improving pullout resistance, as well as decreasing cephalocaudad toggling and implant loosening. We hypothesized the elastic properties of immature bone may mitigate, and perhaps enhance the purported benefits of the hubbing technique. We set out to evaluate pullout strength of fixed-head pedicle screws after hubbing versus standard insertion in the immature thoracic calf spine. Twenty-two (n=22) single-level disarticulated fresh-frozen immature calf thoracic vertebra specimens (ranging from T2 to T13) were prepared. Twelve specimens were instrumented with pedicle screws in group I (nonhubbed) and group II (hubbed) in the opposite pedicle. Cyclic loading in a cephalocaudad direction was applied for 2000 cycles at a rate of 1 Hz. Pullout testing was performed in-line with the midline of the vertebra and peak pullout strength was measured in Newtons. Ten different specimens underwent micro-computed tomography evaluation to assess for trabecular architecture and incidence of iatrogenic microfractures. Hubbed screws resulted in significantly lower pullout strength (747±197 vs. 922±112 N, P=0.01). With the hubbing technique, the dorsal cortex demonstrated plastic deformation and conformed to the screw head in 83% of cases compared with no visible plastic deformation in the control group. Micro-computed tomography demonstrated microfractures of the dorsal cortex in 10/10 for the hubbed group compared with 1/10 for the control group. This is the largest study ever performed on immature thoracic vertebra to evaluate this topic. Hubbed pedicle screws have significantly decreased pullout strength and frequently cause iatrogenic microfractures of the dorsal cortex. The unique ability of immature bone to exhibit plastic deformation did not provide a protective effect on immediate fixation strength, and the increased insertional torque during the hubbing technique should not give a false sense of added fixation. This study, along with our adult study, provides critical information to the surgeon to avoid this common misunderstanding with screw insertion technique. In vitro fresh-frozen immature calf spine study.
    Journal of pediatric orthopedics 03/2014; · 1.23 Impact Factor
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    ABSTRACT: Study Design. Prospectively enrolled, retrospectively analyzed case series.Objective. Evaluate a large series of pediatric/adult spinal deformity patients undergoing surgery with posterior column osteotomies (PCO).Summary of Background Data. Osteotomies of the posterior column (Smith-Petersen or Ponté) are utilized to reduce kyphosis, increase lordosis or increase spinal flexibility. However, little focused evidence exists regarding the efficacy and safety of this technique.Methods. 128 consecutive patients underwent posterior spinal instrumented fusion (PSF) with PCOs with minimum 2-year follow-up. 75 were primary surgeries; 53 were revisions. Data were collected from hospital charts, clinic notes, radiographs and standardized questionnaires [Scoliosis Research Society-30 (SRS-30) and Oswestry Disability Index (ODI)].Results. 128 patients aged 37.6±21 years underwent 518 PCOs (mean, 4.0±2.2) with 14.4±3 mean instrumentation levels, with 3-year (range, 2-6.8) average follow-up. PCOs were used for kyphosis correction in 49%, scoliosis correction at the apex of a curve in 13%, and both in 38%. 106 patients had complete radiographic data available for evaluation. Mean kyphosis correction per PCO was 8.8°±7.2, varying with patient age (10.2° for <21 vs. 7.7° for ≥21, P<0.0001) and region of the spine: Thoracolumbar (TL, T10-L2) 11.6° > lumbar (L, L2-S1) 9.4° > mid-thoracic (MT, T6-10) 7.2° > proximal thoracic (PT, T1-T6) 3.6°. With PCOs at the apex of a curve, max coronal Cobb decreased from 66°±21 to 31°±14 (P<0.0001). Average estimated blood loss (EBL) was 1419±887mL, correlating with greater age (P<0.0001) and more instrumented levels (P<0.0001), but not with number of PCOs (P = 0.32). Complications occurred in 31 (24.2%) patients, including 4 radiculopathies (none attributable to PCOs). Complications did not correlate with number of PCOs (P = 0.5). Six (4.7%) patients had loss of spinal cord monitoring or a failed wake-up test that could be attributed to overcorrection with PCOs, but none had postoperative deficits. ODI scores improved (34.4±17 to 23.6±18, P<0.0001), as did normalized SRS-30 scores (63.7±13 to 76.4±15, P<0.0001).Conclusion. Patients in this series undergoing PSF with PCOs achieved overall favorable outcomes for spinal deformity correction. The number of PCOs did not correlate with increased EBL or complications. The main technical concern was overcorrection, but neurologic consequences associated with overcorrection were identified by intraoperative SCM and wake-up tests, and no patients suffered permanent neurologic deficits related to PCOs.
    Spine 02/2014; · 2.16 Impact Factor
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    ABSTRACT: Object Chiari malformation Type I (CM-I) is a developmental abnormality often associated with a spinal syrinx. Patients with syringomyelia are known to have an increased risk of scoliosis, yet the influence of specific radiographically demonstrated features on the prevalence of scoliosis remains unclear. The primary objective of the present study was to investigate the relationship of maximum syrinx diameter and tonsillar descent to the presence of scoliosis in patients with CM-I-associated syringomyelia. A secondary objective was to explore the role of craniovertebral junction (CVJ) characteristics as additional risk factors for scoliosis. Methods The authors conducted a retrospective review of pediatric patients evaluated for CM-I with syringomyelia at a single institution in the period from 2000 to 2012. Syrinx morphology and CVJ parameters were evaluated with MRI, whereas the presence of scoliosis was determined using standard radiographic criteria. Multiple logistic regression was used to analyze radiological features that were independently associated with scoliosis. Results Ninety-two patients with CM-I and syringomyelia were identified. The mean age was 10.5 ± 5 years. Thirty-five (38%) of 92 patients had spine deformity; 23 (66%) of these 35 patients were referred primarily for deformity, and 12 (34%) were diagnosed with deformity during workup for other symptoms. Multiple regression analysis revealed maximum syrinx diameter > 6 mm (OR 12.1, 95% CI 3.63-40.57, p < 0.001) and moderate (5-12 mm) rather than severe (> 12 mm) tonsillar herniation (OR 7.64, 95% CI 2.3-25.31, p = 0.001) as significant predictors of spine deformity when controlling for age, sex, and syrinx location. Conclusions The current study further elucidates the association between CM-I and spinal deformity by defining specific radiographic characteristics associated with the presence of scoliosis. Specifically, patients presenting with larger maximum syrinx diameters (> 6 mm) have an increased risk of scoliosis.
    Journal of Neurosurgery Pediatrics 02/2014; · 1.63 Impact Factor
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    ABSTRACT: Study Design. Case Control StudyObjective. To evaluate risk factors in patients in 3 groups, those without PJK (N), with PJK but not requiring revision (P) and then those with PJK requiring revision surgery (S).Summary of Background Data. It is becoming clear that some patients maintain stable PJK angles, while others progress and develop severe PJK necessitating revision surgery.Methods. 206 pts at a single institution from 2002-2007 with adult scoliosis with 2 yr min f/u (avg. 3.5 yrs) were analyzed. Inclusion criteria were age > 18, primary fusions >5 levels from any thoracic UIV to any LIV. Revisions were excluded. Radiographic assessment included Cobb measurements in the coronal/sagittal plane and measurements of the PJK angle at post-operative timepoints: 1-2 months, 2 yrs and final f/u. PJK was defined as an angle >10°.Results. The prevalence of PJK was 34%. The average age in N was 49.9 vs. 51.3 in P and 60.1 in S. Gender, Body Mass index (BMI), smoking status were not significantly different between groups. Fusions extending to the pelvis were 74%, 85% and 91% of the cases in Groups N, P and S. Instrumentation type was significantly different between groups N and S with a higher number of UIV hooks in group N. Radiographic parameters demonstrated a higher postop LL and a larger sagittal balance (SVA) change with surgery in those with PJK requiring revision surgery. SRS post-op pain scores were inferior in group N vs. P and S and ODI scores were similar between all groups.Conclusion. PJK patients requiring revision were older, had higher postop LL and larger SVA corrections than patients without PJK. Based on this data, it appears as though older patients with large corrections in their LL and SVA were at risk for developing PJK requiring revision surgery.
    Spine 01/2014; · 2.16 Impact Factor
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    ABSTRACT: Study Design. Retrospective review of prospectively collected databases.Objective. To compare two approaches for assessment of mortality associated with spine surgery.Summary of Background Data. The Scoliosis Research Society (SRS) collects morbidity and mortality (M&M) data from its members. Previously this included details for all spine cases and all complications. To reduce time burden and improve compliance, collection was changed to focus on a few major complications (death, neurologic deficit, and blindness) for specific deformity diagnoses (scoliosis, spondylolisthesis, and kyphosis) and only for cases with complications.Methods. Data were extracted from the SRS from 2004-2007 (detailed system) and 2009-2011 (simplified system). As an anchor for comparison, mortality rates were compared between the systems.Results. Between 2009-2011, 87,162 deformity cases were reported, with 131 deaths (1.50/1,000 cases). Of these 131 patients, mean age was 50, mean ASA grade was 2.8, 10% were smokers, and 18% had diabetes. Rates of death (per 1,000 cases) were: idiopathic scoliosis (0.4), congenital scoliosis (1.3), neuromuscular scoliosis (3.6), other scoliosis (3.1), spondylolisthesis (0.6), and kyphosis (4.7). Common causes of mortality included respiratory (48), cardiac (32), sepsis (12), organ failure (9), and blood loss (7). Compared with the detailed system, the simplified system had greater surgeon compliance (79% versus 62%, p<0.001), greater number of deformity cases/reporting surgeon/year (139 versus 90, p<0.001) and had modestly but significantly lower mortality rates (1.50 versus 1.80/1,000 cases; p<0.001). Causes of death were comparable between the two systems.Conclusion. Based on the simplified collection system, the rate of mortality for spinal deformity surgery was 1.50/1,000 cases. Compared with the detailed system, the simplified system had significantly improved compliance and similar mortality rates. Although the simplified system is limited by less data collected, it achieves better compliance and may prove effective, especially if supplemented with focused data collection modules.
    Spine 01/2014; · 2.16 Impact Factor

Publication Stats

10k Citations
875.68 Total Impact Points

Institutions

  • 2006–2013
    • University of Utah
      Salt Lake City, Utah, United States
    • The University of Tokyo
      • Department of Surgical Sciences
      Tokyo, Tokyo-to, Japan
  • 1995–2013
    • Barnes Jewish Hospital
      San Luis, Missouri, United States
  • 1992–2013
    • Washington University in St. Louis
      • • Department of Orthopaedic Surgery
      • • Department of Anesthesiology
      Saint Louis, MO, United States
  • 2012
    • University of California, Los Angeles
      • Department of Orthopaedic Surgery
      Los Angeles, CA, United States
    • Harvard Medical School
      Boston, Massachusetts, United States
    • Miami Children's Hospital
      Miami, Florida, United States
  • 2002–2012
    • Walter Reed National Military Medical Center
      • • Division of Orthopaedic Surgery
      • • Department of Orthopaedics and Rehabilitation
      Washington, Washington, D.C., United States
    • Madigan Army Medical Center
      Tacoma, Washington, United States
    • University of Missouri
      • Department of Orthopaedic Surgery
      Columbia, MO, United States
  • 2011
    • Uniformed Services University of the Health Sciences
      • Department of Surgery
      Bethesda, MD, United States
    • Kyushu University
      Hukuoka, Fukuoka, Japan
    • Johns Hopkins University
      • Department of Orthopaedic Surgery
      Baltimore, MD, United States
    • Chinese PLA General Hospital (301 Hospital)
      • Department of Orthopaedics
      Beijing, Beijing Shi, China
    • St.Mary's Hospital (Fukuoka - Japan)
      Hukuoka, Fukuoka, Japan
  • 2009–2011
    • Shriners Hospitals for Children
      Tampa, Florida, United States
    • Keio University
      Edo, Tōkyō, Japan
    • Rady Children's Hospital
      San Diego, California, United States
    • Meijo University
      Nagoya, Aichi, Japan
  • 2010
    • Stanford University
      • Department of Orthopaedic Surgery
      Stanford, CA, United States
  • 2005–2009
    • Inha University
      • Department of Orthopaedic Surgery
      Seoul, Seoul, South Korea
    • California State University, Sacramento
      Sacramento, California, United States
  • 2008
    • Seoul Veterans Hospital
      Sŏul, Seoul, South Korea
    • Niigata University
      Niahi-niigata, Niigata, Japan
    • Texas Scottish Rite Hospital for Children
      Texas City, Texas, United States
    • St. Luke's Hospital (MO, USA)
      Saint Louis, Michigan, United States
    • Chungnam National University
      • Department of Orthopaedic Surgery
      Daiden, Daejeon, South Korea
    • Duke University Medical Center
      • Department of Orthopaedic Surgery
      Durham, NC, United States
  • 2005–2008
    • University of California, San Diego
      • Department of Orthopaedic Surgery
      San Diego, CA, United States
  • 2007
    • Wooridul Spine Hospital Group
      Sŏul, Seoul, South Korea
  • 2000
    • Children's Hospital of Richmond
      Richmond, Virginia, United States
  • 1993–2000
    • Johns Hopkins Medicine
      • • Department of Orthopaedic Surgery
      • • Department of Neurology
      Baltimore, MD, United States
  • 1998
    • The Ohio State University
      Columbus, Ohio, United States
  • 1990–1991
    • University of Washington Seattle
      • Department of Surgery
      Seattle, WA, United States