Publications by authors named "Christopher J Kleck"

23 Publications

  • Page 1 of 1

Expectoration of anterior cervical discectomy and fusion cage: a case report.

J Spine Surg 2021 Jun;7(2):218-224

Division of Spine Surgery, Department of Orthopaedics, University of Colorado School of Medicine, Aurora, CO, USA.

Anterior cervical implant failure can lead to catastrophic sequalae and requires prompt evaluation and management to reduce significant morbidity. This case report describes a 51-year-old female who underwent a C2-3 and C3-4 anterior cervical discectomy and fusion (ACDF) with stand-alone, integrated plate-cage interbody devices for cervical spondylotic myelopathy (CSM). Initial procedure was performed at an outside institution. Unfortunately, no radiographic follow up was obtained by the primary surgeon during the initial post-operative period. Post-operatively she experienced persistent dysphagia and troubles swallowing. The patient was eventually seen by the ear, nose and throat (ENT) service at our institution. Eighteen months after the index procedure, a nasolaryngoscopy revealed exposure of her ACDF implant through the posterior aspect of her pharynx. The ENT service obtained radiographs and immediately contacted our Spine Surgery service. Repeat anterior approach with implant removal was planned; however, during the interim, the patient suffered a coughing fit and complete expectoration of the C2-3 implant with the locking screws in place had occurred. Patient experienced immediate relief of symptoms. Miraculously, the patient did not develop airway compromise, infection, or return of severe dysphagia symptoms. During continued follow up, no significant clinical sequelae of her anterior cervical soft tissue structures were identified. The patient chose to decline further surgical management of her cervical spine. This case report highlights a potentially catastrophic complication following ACDF. Several modifiable factors including implant design, C2-3 ACDF cage placement, use of post-operative radiographs, and patient education regarding need for consistent follow up may have prevented this complication. Implant extrusion is a rare, but potentially serious complication following ACDF. Presenting symptoms can be generalized and mild including pain, swelling, or worsening dysphagia. It is paramount to obtain orthogonal X-rays for routine follow-up of post-surgical ACDF patients, especially if dysphagia persists or worsens. Immediate surgical management in recommended if significant post-operative cage migration is encountered.
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http://dx.doi.org/10.21037/jss-20-655DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261561PMC
June 2021

Postoperative pelvic incidence (PI) change may impact sagittal spinopelvic alignment (SSA) after instrumented surgical correction of adult spine deformity (ASD).

Spine Deform 2021 Jul 19;9(4):1093-1104. Epub 2021 Apr 19.

Department of Orthopedics, University of Colorado Anschutz Medical Campus, 12631 E. 17th Ave., Mail Stop B202, Aurora, CO, 80045, USA.

Objectives: To study factors causing postoperative change of PI after surgical correction of ASD and to assess the effect of this variability on postoperative PI-LL mismatch.

Background: PI is used as an individual constant to define lumbar lordosis (LL) correction goal (PI-LL < 10). Postoperative changes of PI were shown but with opposite vectors. The impact of the PI variability on the postoperative PI-LL has not been studied.

Methods: The medical and radiographic data analyzed for patients who underwent long posterior instrumented spinal fusion. Inclusion criteria are age, ≥ 20 years old; ASD due to degenerative disk disease (DDD) or scoliosis (DS); ≥ 3 levels fused; and 2-year follow-up or revision. Studied parameters are LL (L1-S1), PI, sacral slope (SS), pelvic tilt (PT), and PI-LL. Measurement error and postoperative changes were defined. Statistical analysis includes ANOVA, correlation, regression, and risk assessment by odds ratio; P ≤ 0.05 considered statistically significant.

Results: Eighty patients were included: mean age, 62.4 years-old (SD, 11.1); female, 63.7%; mean body mass index (BMI), 27.1 (SD, 5.6). Distribution of patients by follow-ups includes preoperative 100%; postoperative (1-3 weeks), 100%; 11-13 months. 90%; 22-26 months, 58%; and revision: 24%. Pre- versus postoperative PI (∆PI) changed both positively and negatively and the absolute value of change|∆PI| exceeded measurement error (P ≤ 0.05) reaching as high as 31°, and progressed with time; R dropped from 0.73 to 0.45 (P < 0.001); ∆PI depended on disproportional changes of SS and PT, preoperative PI, and change of LL. Obesity, DS, and absence of sacroiliac fixation increased |∆PI|. The risk of LL insufficient correction (PI-LL > 10°) associated with a |∆PI|> 6°, P = 0.05. Sacroiliac fixation diminished PI variability only during the first postoperative year.

Conclusion: Preoperative variability and postoperative instability of PI diminish the applicability of the PI-LL < 10° goal to plan correction of LL. An alternative method is offered.

Level Of Evidence: IV.
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http://dx.doi.org/10.1007/s43390-020-00283-2DOI Listing
July 2021

Radius of Curvature in Patient-Specific Short Rod Constructs Versus Standard Pre-Bent Rods.

Int J Spine Surg 2020 Dec 29;14(6):944-948. Epub 2020 Dec 29.

Department of Orthopedics, University of Colorado, Anschutz Medical Campus, Aurora, Colorado.

Background: Recent studies support the need for sagittal alignment restoration when performing lumbar degenerative spinal fusions. The development of patient-specific spine rods (PSSRs) may help maintain or improve sagittal alignment in these surgeries.

Methods: A retrospective review was conducted for patients who underwent posterior spinal surgeries involving 4 or less levels. The preplanned PSSR radii of curvature (ROC) was compared with standard prebent rods with a ROC of 125 mm. All surgeries were performed at a single institution by 3 surgeons from September 2016 through October 2018. Data were then compared using a 2-tailed paired test. PSSR had either 1 or 2 definitive ROCs.

Results: For rods with 2 ROCs, the "cranial" curve was measured between the upper instrumented level and L4 or L5. The "caudal" curve was measured between L4 or L5 and the lower instrumented level. The PSSR with 1 ROC and the caudal portion of the rods with 2 ROCs were significantly smaller than the industry standard ROC.

Conclusions: PSSR demonstrate more acute ROC than industry standard rods. In PSRs, the most lordosis occurs between L4-S1 and flattens out at the thoracolumbar junction, mimicking the normal distribution of lumbar lordosis. PSSRs could help achieve or maintain sagittal alignment and prevent the sequela of flat back syndrome.
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http://dx.doi.org/10.14444/7143DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872407PMC
December 2020

Toxicology Screening Testing in Patients Undergoing Spine Surgery: A Prospective Observational Pilot Study.

Ther Drug Monit 2021 02;43(1):136-138

Department of Anesthesiology, University of Colorado School of Medicine.

Background: Chronic opioid use and polypharmacy are commonly seen in chronic pain patients presenting for spine procedures. Substance abuse and misuse have also been reported in this patient population. Negative perioperative effects have been found in patients exposed to chronic opioid, alcohol, and recreational substances. Toxicology screening testing (TST) in the perioperative period provides useful information for adequate preoperative optimization and perioperative planning.

Methods: We designed a pilot study to understand this population's preoperative habits including accuracy of self-report and TST-detected prescribed and unprescribed medications and recreational substances. We compared the results of the TST to the self-reported medications using Spearman correlations.

Results: Inconsistencies between TST and self-report were found in 88% of patients. Spearman correlation was 0.509 between polypharmacy and intraoperative propofol use, suggesting that propofol requirement increased as the number of substances used increased.

Conclusions: TST in patients presenting for spine surgery is a useful tool to detect substances taken by patients because self-report is often inaccurate. Discrepancies decrease the opportunity for preoperative optimization and adequate perioperative preparation.
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http://dx.doi.org/10.1097/FTD.0000000000000837DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7803444PMC
February 2021

Vertebral Osteomyelitis.

J Am Acad Orthop Surg Glob Res Rev 2019 Dec 5;3(12). Epub 2019 Dec 5.

Department of Orthopaedic Surgery (Dr. McGee, Dr. Dean, and Dr. Kleck), The University of Colorado, Aurora, CO; the Division Plastics and Reconstructive (Dr. Ignatiuk), Department of Surgery, Rutgers New Jersey Medical School, Newark, NJ; and the Department of Infectious Diseases (Dr. Savelli), The University of Colorado School of Medicine, Aurora, CO.

A report of an instance of vertebral osteomyelitis secondary to an uncommon pathogen, .

Summary: is a rapidly growing nontuberculous osteomyelitis which is typically nonpathogenic with only four reported cases of human infection. Diagnosing infections related to nontuberculous mycobacteria (NTM) is difficult and can often be delayed as conventional microbiologic tests are inadequate. Currently, there are no consensus guidelines concerning the treatment of vertebral osteomyelitis caused by NTM. A 45-year-old man presented with chronic back pain and bilateral lower extremity radicular symptoms status-post lumbar fusion with previous deep infection. CT scan demonstrated incomplete union after fusion. He underwent irrigation and débridement on March 15, 2016, with tissue culture and biopsy. Given negative cultures and completion of a 6-week course of intravenous antibiotics, on May 3, 2016, he went for implant removal and repeat instrumentation. During the same hospitalization, deep spinal fluid acid-fast bacilli culture from March 15, 2016, came back positive at 8 weeks, identified as . He was started on an empiric 4-drug regimen for NTM which he continued for 12 months. There has been no recurrence of infection to date.

Discussion: This case serves as the first description of osteomyelitis of the spine and as a reminder that proper diagnosis of infectious etiologies is necessary for adequate treatment.
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http://dx.doi.org/10.5435/JAAOSGlobal-D-18-00069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004494PMC
December 2019

Strap stabilization for proximal junctional kyphosis prevention in instrumented posterior spinal fusion.

Eur Spine J 2020 06 14;29(6):1287-1296. Epub 2020 Jan 14.

Department of Orthopedics, University of Colorado, Anschutz Medical Campus, 1365 N. Aurora Court, Aurora, CO, USA.

Study Design: This is a retrospective, single-institution, cohort study.

Objectives: To evaluate the association of Mersilene tape use and risk of proximal junctional kyphosis (PJK), after surgical correction of adult spinal deformity (ASD) by posterior instrumented fusion (PIF). PJK, following long spinal PIF, is a complication which often requires reoperation. Mersilene tape, strap stabilization of the supra-adjacent level to upper instrumented vertebra (UIV) seems a preventive measure.

Methods: Patients who underwent PIF for ASD with Mersilene tape stabilization (case group) or without (control group) between 2006 and 2016 were analyzed preoperatively to 2-year follow-up. Matching of potential controls to each case was performed. Radiographic sagittal Cobb angle (SCA), lumbar lordosis, pelvic tilt, sacral slope, and pelvic incidence were measured pre- and postoperatively, using a deformity measuring software program. PJK was defined as progression of postoperative junctional SCA at UIV ≥ 10°.

Results: Eighty patients were included: 20 cases and 60 controls. The cumulative rate of PJK ≥ 10° at 2-year follow-up was 15% in cases versus 38% of controls (OR = 0.28; P = 0.04) with higher latent period in cases, (20 vs. 7.5 months), P = 0.018. Mersilene tape decreased risk of PJK linked with the impact of the following confounders: age, ≥ 55 years old (OR = 0.19; 0.02 ≥ P ≤ 0.03); number of spinal levels fused 7-15 (OR = 0.13; 0.02 ≥ P ≤ 0.06); thoracic UIV (T12-T1) (OR = 0.13; 0.02 ≥ P ≤ 0.06); BMI ≥ 27 kg/m (OR = 0.22; 0.03 ≥ P ≤ 0.08); and osteoporosis (OR = 0.13; 0.02 ≥ P ≤ 0.08).

Conclusions: Mersilene tape at UIV + 1 level decreases the risk of PJK following PIF for ASD. These slides can be retrieved under Electronic Supplementary Material.
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http://dx.doi.org/10.1007/s00586-020-06291-0DOI Listing
June 2020

Transpedicular-Transdiscal Cement Augmentation Treatment of Thoracolumbar Fusion Proximal Junctional Failure.

Int J Spine Surg 2019 Oct 31;13(5):470-473. Epub 2019 Oct 31.

University of Colorado, Aurora, Colorado.

Background: Long instrumented fusions for adult deformity have a proximal junction kyphosis rate between 20% and 40%. When symptomatic, proximal junctional failure (PJF) often requires revision surgery and is associated with significant morbidity. Vertebral cement augmentation (VCA) has been used for prophylaxis against PJF but has not been previously described as treatment after onset of PJF has occurred. We describe a series of patients with PJF of long posterior spinal fusions that were treated at our institution using a novel VCA technique.

Methods: Three patients with PJF above thoracolumbopelvic fusions were retrospectively reviewed following treatment with transpedicular-transdiscal VCA. The medical record was reviewed for demographic data, outcomes scores, and radiographic images.

Results: Mean age was 69.3 years. Mean follow-up was 13.3 months. Mean preprocedure visual analog scale score was 8.67, and postprocedure visual analog scale score was 4.00. Mean preprocedure sagittal balance was 9.7 cm, and postprocedure sagittal balance was 5.8 cm. No patients required revision surgery for PJF in the follow-up period.

Conclusions: Transpedicular-transdiscal VCA treatment for PJF is safe and may have the potential to prevent the need for revision surgery.

Level Of Evidence: 4.
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http://dx.doi.org/10.14444/6062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6833968PMC
October 2019

Long-Term Treatment Effect and Predictability of Spinopelvic Alignment After Surgical Correction of Adult Spine Deformity With Patient-Specific Spine Rods.

Spine (Phila Pa 1976) 2020 Apr;45(7):E387-E396

Department of Orthopedics, University of Colorado, Anschutz Medical Campus, Aurora, CO.

Study Design: Retrospective case series.

Objective: To evaluate the short- and long-term treatment effect (TE) of spinopelvic parameters after surgical correction of adult spine deformity (ASD) utilizing preoperative planning and patient-specific spine rods (PSSRs), and to assess the correspondence between planned and real outcomes.

Summary Of Background Data: PSSR have been used in ASD correction for the last decade. However, a TE and predictability of spinopelvic alignment at long-term follow-up has not been studied.

Methods: Inclusion criteria: male or female; age more than 20 years; correction of ASD with PSSR; 24-month follow-up (or revision surgery). Studied parameters: sagittal vertical axis; lumbar lordosis (LL); pelvic tilt (PT); sacral slope; pelvic incidence (PI); and PI-LL. The measurement error, TE (the differences between postoperative and preoperative values), standardized TE, and predictability of the studied parameters assessed. The variables included categorical (optimal/nonoptimal) and continuous obtained by direct measurements and weighted by individual optimal values. Statistical significance was set at P ≤ 0.05.

Results: Thirty-four patients were included: 56% women; the mean age, 63.4 (standard deviation, 12.7); at each follow-up: 32 at 1 to 3 months, 34 at 11 to 13, and 14 at 23 to 25 with 9 followed to the revision surgery. Strong or moderate TE was shown for sagittal vertical axis, LL, and PI-LL. The TE of PT and sacral slope was less significant and lower than planned. PI was not stable in 18%. The changes of continuous variables were more prominent and statistically significant then categorical. The mean values did not show significant differences between planned and postoperative outcomes except for PT. However, the individual deviations were substantial for all parameters. Significant predictability was shown only for LL and PI.

Conclusion: Use of PSSR showed strong and relatively stable TE in ASD during 2 postoperative years. However, improvement of the planning accuracy may contribute to further enhancement of the method's efficacy.

Level Of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003290DOI Listing
April 2020

Mini-open sacroiliac joint fusion with direct bone grafting and minimally invasive fixation using intraoperative navigation.

J Spine Surg 2019 Mar;5(1):31-37

Department of Orthopedics, University of Colorado, Aurora, CO, USA.

Background: Describe a novel technique for sacroiliac arthrodesis using intraoperative navigation, direct bone grafting, and minimally invasive implants. Report on the outcomes of the first cohort of these patients.

Methods: Institutional review board (IRB) approved, single center, two surgeon, retrospective study.

Results: All patients were 18 years or older, primary sacroiliac fusions, and underwent novel technique described. Fifty patients underwent 57 surgeries. Twelve male/38 female patients. All received three sacroiliac implants. Average blood loss 42.8 mL. Average length of stay 1.9 nights. Average follow-up 13.96±13 months. Statistically significant improvements in Visual Analogue Scale (VAS) scores (<0.001) for all time periods 6 weeks, 3 months, 6 months, 12 months compared to preop. Other outcomes scores [Oswestry Disability Index (ODI), and Denver Sacroiliac Joint Questionnaire (DSIJQ)] also showed a general trend for clinical improvement at all postoperative time periods. Of 2/57 (3.5%) complications were identified. No patients required surgical revision within the study window.

Conclusions: Limited open sacroiliac arthrodesis using minimally invasive implants, intraoperative navigation, and direct open bone grafting is safe and demonstrates clinical benefit, similar to other techniques for minimally invasive sacroiliac arthrodesis. There is potential for improved long-term outcomes from increased union rates.

Keywords: Sacroiliac dysfunction; minimally invasive sacroiliac fusion; open sacroiliac fusion; navigation.
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http://dx.doi.org/10.21037/jss.2019.01.04DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465478PMC
March 2019

Patient-specific Rods for Surgical Correction of Sagittal Imbalance in Adults: Technical Aspects and Preliminary Results.

Clin Spine Surg 2019 03;32(2):80-86

Spinal Unit, Santy Orhopaedic Center and Mermoz Hospital Ramsay GDS, Lyon, France.

Study Design: This was an innovative concept and a preliminary prospective series.

Objective: The aim of this study was to present the concept and the technical aspects of patient-specific rods (PSR), and compare preoperative and postoperative sagittal parameters (after PSR implantation), with a special focus on the difference pelvic incidence (PI)-lumbar lordosis (LL).

Background: Despite established techniques for planning and proven correlations between quality of life and sagittal alignment, some patients do not achieve optimal radiologic outcomes after surgery and are still hypolordotic and imbalanced. We hypothesize that the use of PSR could improve the correspondence between planning and surgical realization.

Methods: The planning was based on spinopelvic parameters evaluated on a full-spine x-ray. The surgical procedure including osteotomies was simulated using a dedicated program to reach the following objectives: PI-LL<10 degrees, a pelvic tilt <20 degrees, and sagittal vertical axis <50 mm. From the virtually corrected spine, the rod curvature and length were defined. Two PSRs were thus precisely manufactured and bent to this specification. Adults with degenerative spinal disorders requiring a construct ≥5 levels were implanted with PSR and prospectively included. We compared ratios through the χ test.

Results: A total of 60 patients (mean age of 64.4 years old; range, 34-83) were included. Follow-up was carried out over a period of 1 year. Average pedicle screws construct was of 6.4 levels (range, 5-9). Eight patients underwent a pedicle subtraction osteotomy. PI-LL was <10 degrees at baseline in 29/60 patients, and at follow-up in 50/60 (odds ratio=5, P=E-5).

Conclusions: The ratio of patients with optimal PI-LL improved significantly from PSR implantation. In comparison with published data for conventional surgery, patients implanted with PSR were 2.6 times more likely to be optimally corrected. The expected benefits of PSR include the optimal execution of the plan, decreased mechanical complications, and reduced operating time, no longer requiring the bending of rods during surgery. A randomized trial on sagittal correction using PSR is ongoing.
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http://dx.doi.org/10.1097/BSD.0000000000000721DOI Listing
March 2019

Surgical Intervention for Cauda Equina Syndrome in the Second and Third Trimesters of Pregnancy: A Report of Three Cases.

JBJS Case Connect 2018 Jul-Sep;8(3):e68

Department of Orthopaedics, Anschutz Medical Campus, University of Colorado, Aurora, Colorado.

Case: Low back pain affects >50% of pregnant women. However, cauda equina syndrome (CES) during pregnancy is rare. Because a delay in treatment increases the risk of irreversible neurologic damage, acute onset is regarded as a surgical emergency. We describe 3 cases of CES in pregnant women at 24, 27, and 30 weeks' gestation, respectively.

Conclusion: All 3 of the patients underwent surgical decompression in the prone position under general anesthesia with continuous external monitoring of the fetal heart rate. Intraoperative findings were noteworthy for epidural venous plexus engorgement in 2 of the patients. There were no complications for the patients or the fetuses, and all 3 of the patients had postoperative resolution of the neurologic symptoms.
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http://dx.doi.org/10.2106/JBJS.CC.17.00289DOI Listing
November 2019

Stand-alone Anterior Lumbar Interbody, Transforaminal Lumbar Interbody, and Anterior/Posterior Fusion: Analysis of Fusion Outcomes and Costs.

Orthopedics 2018 Sep 16;41(5):e655-e662. Epub 2018 Jul 16.

Fusion outcomes and costs of stand-alone anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody fusion (TLIF) in association with posterior fusion, and anterior/posterior (A/P) fusion were compared using clinical, radiographic, and billing data. Adult patients with symptomatic 1- or 2-level degenerative disk disease in isolation or in association with a grade 1 or 2 degenerative or lytic spondylolisthesis and canal and/or foraminal stenosis who underwent elective stand-alone ALIF, TLIF, or A/P fusion were compared. The analysis focused primarily on fusion rates and costs and secondarily on radiographic and clinical parameters. One hundred six patients at least 2 years beyond surgery (ALIF, 53; TLIF, 17; A/P fusion, 36) were reviewed. Demographics were similar except for age, with the ALIF group being younger (mean, 37.8 years) than the other groups (TLIF, 53.1 years; A/P fusion, 48.2 years). There were no differences between the groups in fusion rates or outcomes as assessed by the Numeric Rating Scale. Compared with the other 2 groups, the ALIF group had a significantly shorter operative time, less blood loss, and a shorter stay (P<.0001). Evaluation of radiographic parameters revealed significant differences regarding disk angle (P<.001), disk height (P<.0001), and pelvic tilt (P=.001) favoring ALIF and A/P fusion over TLIF. Stand-alone ALIF should be considered in the management of patients with 1- or 2-level lumbar degenerative disk disease for which the pathology can be addressed adequately via this approach. [Orthopedics. 2018; 41(5):e655-e662.].
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http://dx.doi.org/10.3928/01477447-20180711-06DOI Listing
September 2018

Correction to: The relationship of pelvic incidence to post-operative total hip arthroplasty dislocation in patients with lumbar fusion.

Int Orthop 2018 10;42(10):2307

Department of Orthopedics, The University of Colorado, 12631 E 17th Ave, Rm 4501, Aurora, CO, 80045, USA.

The original publication of this paper contain an error. The author name "Alan S. McGee Jr" is incorrect for it should have been "Alan W. McGee Jr".
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http://dx.doi.org/10.1007/s00264-018-3973-0DOI Listing
October 2018

The relationship of pelvic incidence to post-operative total hip arthroplasty dislocation in patients with lumbar fusion.

Int Orthop 2018 10 28;42(10):2301-2306. Epub 2018 Apr 28.

Department of Orthopedics, The University of Colorado, 12631 E 17th Ave, Rm 4501, Aurora, CO, 80045, USA.

Purpose: To determine if lumbar fusion increases the risk of dislocation following total hip arthroplasty (THA) via a posterior approach and to investigate anatomic variables associated with this increased risk.

Methods: Five-year retrospective review of THAs performed through a posterior approach identifying cases of post-operative dislocation. Patients were grouped into those with or without previous lumbar spine fusion. Lumbar fusion patients were then further analyzed in terms of cup position, pelvic incidence, sacral slope, and pelvic tilt to determine if there were specific variables associated with the increased risk of dislocation.

Results: Five hundred nine primary THAs in 460 patients (non-simultaneous bilateral THAs in 41 patients) met inclusion criteria with a dislocation rate of 5.5%. Thirty-one patients were identified as having prior lumbar fusions. The dislocation rate was significantly higher in fusion patients (29 vs 4%; p = 0.009) yielding a relative risk (RR) of dislocation of 4.77 (p = < 0.0001). Additionally, cup anteversion was significantly different between groups (26.8 vs 21.42; p = 0.009). Dislocators in the fusion group were also at greater risk of requiring subsequent revision (RR = 3.24; p = 0.003). Subgroup analysis of fusion patients revealed that dislocators had lower pelvic incidence and sacral slope compared to non-dislocators (45.2 vs 58.6 [p = 0.0029] and 26.3 vs 35.6 [p = 0.0384] respectively).

Conclusions: Patients with lumbar fusion are at increased risk for post-operative dislocations requiring revision. Together, lower pelvic incidence and decreased sacral slope are associated with increased risk of dislocation in these patients.
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http://dx.doi.org/10.1007/s00264-018-3955-2DOI Listing
October 2018

Development of Bilateral Facet Cysts Causing Recurrent Symptoms After Decompression and the Placement of an Intralaminar Implant: A Case Report.

JBJS Case Connect 2018 Jan-Mar;8(1):e11

Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, Colorado.

Case: We report the development of bilateral symptomatic facet joint cysts in a 78-year-old man who had been treated with decompression and placement of a coflex device (Paradigm Spine) at L3-L4 and L4-L5. Preoperative imaging clearly demonstrated fluid in the facet joints without cysts. He underwent standard surgical treatment, but developed symptomatic facet joint cysts at 4 months postoperatively. The patient was treated with a revision decompression and replacement of the devices; there were no issues at the 32-month follow-up.

Conclusion: While the coflex device has possible long-term biomechanical advantages, vigilance with adherence to appropriate decompression surgical technique is necessary.
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http://dx.doi.org/10.2106/JBJS.CC.17.00009DOI Listing
November 2019

One-step Minimally Invasive Pedicle Screw Instrumentation Using O-Arm and Stealth Navigation.

Clin Spine Surg 2018 06;31(5):197-202

Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO.

Study Design: Description of a navigated, single-step, minimally invasive technique for the placement of pedicle screws.

Objective: To describe a new technique for minimally invasive placement of pedicle screws in the lumbar spine using O-arm and StealthStation navigation in combination.

Summary Of Background Data: Minimally invasive surgical techniques are described in the literature as safe and effective methods for pedicle screw instrumentation. These techniques increase radiation exposure and prompt multiple instrument passes through the pedicle.

Materials And Methods: In total, 35 adult patients (187 screws) underwent lumbar surgery with pedicle screw placement using the 1- (8 patients/48 screws) or 2-step (27 patients/139 screws) technique. Complications associated with instrumentation were noted. Pedicle screw position was evaluated.

Results: Of 187 screws placed, 181 (96.8%) were found to be fully contained within the pedicle (grade 1) and 4 (2.1%) had a breach of <2 mm. In the 1-step technique, no screws were malpositioned. One screw at S1 with inadequate fixation was replaced with a screw 1 mm larger in diameter. In the 2-step technique, 2 screws (1.06% overall) were revised due to inferior breach of the pedicle. No neurological sequelae were noted. Also, 1 screw was deemed too long at S1 and was replaced with a shorter screw. None of the revised pedicle screws caused neuromonitoring changes and the breaches were found intraoperatively on 3D imaging.

Conclusions: Using O-arm and StealthStation navigation with minimally invasive surgical technology for placement of posterior spinal instrumentation is safe, effective, and limits radiation exposure.
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http://dx.doi.org/10.1097/BSD.0000000000000616DOI Listing
June 2018

Diagnosis and Management of Sacroiliac Joint Dysfunction.

J Bone Joint Surg Am 2017 12;99(23):2027-2036

Department of Orthopaedic Surgery, University of Colorado, Denver, Colorado.

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http://dx.doi.org/10.2106/JBJS.17.00245DOI Listing
December 2017

Strain in Posterior Instrumentation Resulted by Different Combinations of Posterior and Anterior Devices for Long Spine Fusion Constructs.

Spine Deform 2017 Jan;5(1):27-36

Department of Orthopedics, University of Colorado, Anschutz Medical Campus, 13001 E 17th Pl, Aurora, CO 80045, USA.

Study Design: Clinically related experimental study.

Objective: Evaluation of strain in posterior low lumbar and spinopelvic instrumentation for multilevel fusion resulting from the impact of such mechanical factors as physiologic motion, different combinations of posterior and anterior instrumentation, and different techniques of interbody device implantation.

Summary Of Background Data: Currently different combinations of posterior and anterior instrumentation as well as surgical techniques are used for multilevel lumbar fusion. Their impact on risk of device failure has not been well studied. Strain is a well-known predictor of metal fatigue and breakage measurable in experimental conditions.

Methods: Twelve human lumbar spine cadaveric specimens were tested. Following surgical methods of lumbar pedicle screw fixation (L2-S1) with and without spinopelvic fixation by iliac bolt (SFIB) were experimentally modeled: posterior (PLF); transforaminal (TLIF); and a combination of posterior and anterior interbody instrumentation (ALIF+PLF) with and without anterior supplemental fixation by anterior plate or diverging screws through an integrated plate. Strain was defined at the S1 screws, L5-S1 segment of posterior rods, and iliac bolt connectors; measurement was performed during flexion, extension, and axial rotation in physiological range of motion and applied force.

Results: The highest strain was observed in the S1 screws and iliac bolt connectors specifically during rotation. The S1 screw strain was lower in ALIF+PLF during sagittal motion but not rotation. Supplemental anterior fixation in ALIF+PLF diminished the S1 strain during extension. Strain in the posterior rods was higher after TLIF and PLF and was increased by SFIB; this strain was lowest after ALIF+PLF, as supplemental anterior fixation diminished the strain during extension, in particular, cages with anterior screws more than anterior plate. Strain in the iliac bolt connectors was mainly determined by direction of motion.

Conclusions: Different devices modify strain in low posterior instrumentation, which is higher after transforaminal and posterior techniques, specifically with spinopelvic fixation.

Level Of Evidence: N/A.
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http://dx.doi.org/10.1016/j.jspd.2016.09.045DOI Listing
January 2017

Sacroiliac Joint Treatment Personalized to Individual Patient Anatomy Using 3-Dimensional Navigation.

Orthopedics 2016 Mar-Apr;39(2):89-94

During the past 10 years, the sacroiliac (SI) joint has evolved from being barely recognized as a source of pain, to being a joint treated only nonsurgically or with great surgical morbidity, to currently being a joint treated with minimally invasive techniques that are personalized to the individual patient. The complex 3-dimensional anatomy of the SI joint and lack of parallel to traditional imaging planes requires a thorough understanding of the structures within and around the SI joint that may be at risk of injury. Thus, the SI joint is ideally suited for intraoperative 3-dimensional imaging and surgical navigation when being treated minimally invasively.
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http://dx.doi.org/10.3928/01477447-20160304-05DOI Listing
December 2016

A new 3-dimensional method for measuring precision in surgical navigation and methods to optimize navigation accuracy.

Eur Spine J 2016 06 22;25(6):1764-74. Epub 2015 Sep 22.

Department of Orthopedics, University of Colorado Anschutz Medical Campus, 12631 E. 17th Ave, Mail Stop B202, Aurora, CO, 80045, USA.

Purpose: Description of a novel method for evaluation of pedicle screws in 3 dimensions utilizing O-arm(®) and StealthStation(®) navigation; identifying sources of error, and pearls for more precise screw placement.

Methods: O-arm and StealthStation navigation were utilized to place pedicle screws. Initial and final O-arm scans were performed, and the projected pedicle probe track, projected pedicle screw track, and final screw position were saved for evaluation. They were compared to evaluate the precision of the system as well as overall accuracy of final screw placement.

Results: Thoracolumbar deformity patients were analyzed, with 153 of 158 screws in adequate position. Only 5 screws were malpositioned, requiring replacement or removal. All 5 were breached laterally and no neurologic or other complications were noted in any of these patients. This resulted in 97 % accuracy using the navigation system, and no neurological injuries or deficits. The average distance of the screw tip and angle of separation for the predicted path versus the final pedicle screw position were analyzed for precision. The mean screw tip distance from the projected tip was 6.43 mm, with a standard deviation of 3.49 mm when utilizing a navigated probe alone and 5.92 mm with a standard deviation of 3.50 mm using a navigated probe and navigated screwdriver (p = 0.23). Mean angle differences were 4.02° and 3.09° respectively (p < 0.01), with standard deviations of 2.63° and 2.12°.

Conclusions: This new technique evaluating precision of screw placement in 3 dimensions improves the ability to define screw placement. Pedicle screw position at final imaging showed the use of StealthStation navigation to be accurate and safe. As this is a preliminary evaluation, we have identified several factors affecting the precision of pedicle screw final position relative to that predicted with navigation.
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http://dx.doi.org/10.1007/s00586-015-4235-0DOI Listing
June 2016

Epithelioid hemangioma of the distal humerus with pathologic fracture.

Orthopedics 2012 Jan 16;35(1):e116-9. Epub 2012 Jan 16.

Department of Orthopaedics, University of Arizona, Tucson, USA.

Epithelioid hemangioma is a rare tumor that can have bone involvement. Its clinically and radiographically aggressive appearance mimics a malignant neoplasm. Although epitheliod hemangioma has been described as having an aggressive appearance on magnetic resonance imaging (MRI) and plain radiographs, this is the first reported case of pathologic fracture associated with this lesion to our knowledge. This article describes a case of epithelioid hemangioma involving the distal humerus, which initially presented with progressive pain and fracture of the lateral condyle. The aggressive appearance on plain radiographs and MRI suggested a malignant bone tumor. This preliminary diagnosis was confirmed due to the presence of local lymph node spread on positron emission tomography/computed tomography. After a core needle biopsy revealed nondiagnostic tissue, rather than performing a wide resection based on a presumptive malignant diagnosis, we followed the standard diagnostic algorithm and performed an open biopsy with temporary internal stabilization. The tissue sample was adequate and revealed a diagnosis of epithelioid hemangioma. Based on this finding, we were able to proceed with surgical management, including curettage of the lesion, placement of a bone graft, and internal fixation, rather than a wide resection with elbow joint replacement. This article emphasizes the need for careful adherence to the diagnostic algorithm for musculoskeletal tumors. In doing so, a definitive diagnosis was reached, and our patient was able to resume his occupation as a laborer without the restrictions that would have accompanied elbow arthroplasty.
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http://dx.doi.org/10.3928/01477447-20111122-35DOI Listing
January 2012
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