Christopher J. Kleck

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

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. 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.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.

Early Experience and Initial Outcomes With Patient-Specific Spine Rods for Adult Spinal Deformity

The objectives of this study were to describe the process of preoperative planning and using patient-specific rods. This retrospective case series involved 18 patients with adult spinal deformity who were treated with posterior instrumentation and spine fusion, with lumbar or thoracic osteotomies, using patient-specific rods. Data extracted included demographic/surgical variables and preoperative, predicted (surgical plan), and postoperative spinopelvic parameters. The outcome analysis involved assessment of preoperative, planned, and postoperative variables. Treatment effect evaluation involved assessing differences between preoperative and postoperative values and correspondence between planned and achieved results. Surgery using preoperative planned patient-specific rods led to excellent adult spinal deformity correction and spinopelvic alignment.

Pelvic Incidence Changes Between Flexion and Extension

STUDY DESIGN Retrospective single-center. OBJECTIVES To investigate changes in pelvic incidence from flexion to extension. To assess interobserver error in the measurement of pelvic incidence. BACKGROUND Pelvic incidence (PI) has been considered a static parameter since it was originally described. But recent studies have shown that PI can change with age and after spinal procedures. Changes in PI based on position have not been investigated. METHODS Seventy-two patients who had obtained flexion and extension radiographs of the lumbar spine were identified using strict inclusion and exclusion criteria. PI along with pelvic tilt (PT), sacral slope (SS), and lumbar lordosis were measured in both flexion and extension by two independent measurers. Variations in all parameters and interobserver measurement reliability were analyzed for the entire group. RESULTS PI changed significantly from flexion to extension with a general tendency to decrease: mean (-0.94°), p <.044. However, these changes might have had opposite vectors, and exceeded | 6°| (measurement error) in 20% of cases, with a maximum of 12°. Inconsistencies in changes of SS, as opposed to PT from flexion to extension, were found to be the major factor determining changes in PI (p >.001). Obesity significantly contributed to differences in PI between flexion and extension (p = .003). CONCLUSIONS PI is a dynamic parameter that changes between flexion and extension. Changes in SS are the main factor involved in these changes, implicating movement through the sacroiliac joints as the cause. Obese patients have greater changes in PI from flexion to extension. LEVEL OF EVIDENCE Level II.STUDY DESIGN Retrospective single-center. OBJECTIVES To investigate changes in pelvic incidence from flexion to extension. To assess interobserver error in the measurement of pelvic incidence. BACKGROUND Pelvic incidence (PI) has been considered a static parameter since it was originally described. But recent studies have shown that PI can change with age and after spinal procedures. Changes in PI based on position have not been investigated. METHODS Seventy-two patients who had obtained flexion and extension radiographs of the lumbar spine were identified using strict inclusion and exclusion criteria. PI along with pelvic tilt (PT), sacral slope (SS), and lumbar lordosis were measured in both flexion and extension by two independent measurers. Variations in all parameters and interobserver measurement reliability were analyzed for the entire group. RESULTS PI changed significantly from flexion to extension with a general tendency to decrease: mean (-0.94°), p <.044. However, these changes might have had opposite vectors, and exceeded | 6°| (measurement error) in 20% of cases, with a maximum of 12°. Inconsistencies in changes of SS, as opposed to PT from flexion to extension, were found to be the major factor determining changes in PI (p >.001). Obesity significantly contributed to differences in PI between flexion and extension (p = .003). CONCLUSIONS PI is a dynamic parameter that changes between flexion and extension. Changes in SS are the main factor involved in these changes, implicating movement through the sacroiliac joints as the cause. Obese patients have greater changes in PI from flexion to extension. LEVEL OF EVIDENCE Level II.

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

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.].

Bacterial Infection of Spine Instrumentation and MicrobialInfluenced Corrosion (MIC): Chicken or Egg

There is evidence that microbes including bacteria and macrophages are associated with in the presence biomedical alloys implants for orthopedic procedures [1-4]. The corrosion of metal alloys (A316L Surgical stainless steel; ASTM F136 ELI Ti6Al4V; ASTM F75/F1537/F799 CoCrMoC) in-vivo has also been well documented [5-8]. Proprionibacterium acnes as well as Staphylococcus Epidermis are considered sulfur reducing bacteria in the petroleum industry and have been found in petroleum stockpiles and pipelines [9,10]. These bacteria are associated with pipeline corrosion in oil fields and refineries [9]. In our own clinical experiences, we have noted a large number of spine metallosis cases and believe that the corrosion of implants and surgical site infections with P. acnes bacteria, or other sulfur reducing bacteria, are intimately connected in revisions and clinical infections. In our practice we observed an association between infection and implant corrosion leading to the initiation of a study examining revision of spinal instrumentation and patient outcomes. In patients who underwent spine instrumentation revision, who had grey or black stained tissues taken for culture in the OR and subsequent to the revision, we found 4 of 10 having P. acnes and Staph. epidermis present as a latent infection. A few patients showed clinical signs of infection, requiring subsequent drains and wash-out to clear all presence of bacteria. As early as 1999, P. acnes and Staph spp. were shown to be associated with orthopedic infections, where it was detected in 63% of sonicated samples taken from 120 patients receiving total hip revision [4]. As recently as 2016, P. acnes were highlighted as a possible contributor to post operative infections in orthopedic procedures [1]. These commensal skin dwelling microbes are anaerobic, sulfur reducing bacteria [11-13]. P. acnes, Staph. aureus and epidermis have been isolated as biofilm forming bacteria in orthopedics as well [3].

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

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.

Epithelioid hemangioma of the distal humerus with pathologic fracture.

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.