Zinc finger protein-440 promotes cartilage degenerative mechanisms in human facet and knee osteoarthritis chondrocytes

OBJECTIVES

To investigate the role of zinc finger protein 440 (ZNF440) in the pathophysiology of cartilage degeneration during facet joint (FJ) and knee osteoarthritis (OA).

METHODS

Expression of ZNF440 in FJ and knee cartilage was determined by immunohistochemistry, quantitative (q)PCR, and Western blotting (WB). Human chondrocytes isolated from FJ and knee OA cartilage were cultured and transduced with ZNF440 or control plasmid, or transfected with ZNF440 or control small interfering RNA (siRNA), with/without interleukin (IL)-1β. Gene and protein levels of catabolic, anabolic and apoptosis markers were determined by qPCR or WB, respectively. In silico analyses were performed to determine compounds with potential to inhibit expression of ZNF440.

RESULTS

ZNF440 expression was increased in both FJ and knee OA cartilage compared to control cartilage. In vitro, overexpression of ZNF440 significantly increased expression of MMP13 and PARP p85, and decreased expression of COL2A1. Knockdown of ZNF440 with siRNA partially reversed the catabolic and cell death phenotype of human knee and FJ OA chondrocytes stimulated with IL-1β. In silico analysis followed by validation assays identified scriptaid as a compound with potential to downregulate the expression of ZNF440. Validation experiments showed that scriptaid reduced the expression of ZNF440 in OA chondrocytes and concomitantly reduced the expression of MMP13 and PARP p85 in human knee OA chondrocytes overexpressing ZNF440.

CONCLUSIONS

The expression of ZNF440 is significantly increased in human FJ and knee OA cartilage and may regulate cartilage degenerative mechanisms. Furthermore, scriptaid reduces the expression of ZNF440 and inhibits its destructive effects in OA chondrocytes.

Three-stage approach to resection of left pancoast tumour with spinal and major vessel involvement

Here we describe the successful outcome of a complex and challenging resection of a left-sided pancoast tumour involving the left subclavian artery and vertebral bodies. The resection was performed following neoadjuvant chemoradiotherapy in a multi-staged fashion involving multiple teams including thoracic surgery, plastic surgery, neurosurgery and vascular surgery. Each operation was less than 6 h, without complication, and the patient was discharged within 1 week of each procedure. This case report highlights the importance of multidisciplinary team collaboration and planning in order to achieve a successful oncologic outcome and a good quality of life following treatment of these challenging tumours. The patient had a good functional outcome and no evidence of recurrence 1.5 years later.

Sequencing identifies a distinct signature of circulating microRNAs in early radiographic knee osteoarthritis

OBJECTIVE

MicroRNAs act locally and systemically to impact osteoarthritis (OA) pathophysiology, but comprehensive profiling of the circulating miRNome in early vs late stages of OA has yet to be conducted. Sequencing has emerged as the preferred method for microRNA profiling since it offers high sensitivity and specificity. Our objective was to sequence the miRNome in plasma from 91 patients with early [Kellgren-Lawrence (KL) grade 0 or 1 (n = 41)] or late [KL grade 3 or 4 (n = 50)] symptomatic radiographic knee OA to identify unique microRNA signatures in each disease state.

DESIGN

MicroRNA libraries were prepared using the QIAseq miRNA Library Kit and sequenced on the Illumina NextSeq 550. Counts were produced for microRNAs captured in miRBase and for novel microRNAs. Statistical, bioinformatics, and computational biology approaches were used to refine and interpret the final list of microRNAs.

RESULTS

From 215 differentially expressed microRNAs (FDR < 0.01), 97 microRNAs showed an increase or decrease in expression in ≥85% of samples in the early OA group as compared to the median expression in the late OA group. Increasing this threshold to ≥95%, seven microRNAs were identified: hsa-miR-335-3p, hsa-miR-199a-5p, hsa-miR-671-3p, hsa-miR-1260b, hsa-miR-191-3p, hsa-miR-335-5p, and hsa-miR-543. Four novel microRNAs were present in ≥50% of early OA samples and had 27 predicted gene targets in common with the prioritized set of predicted gene targets from the 97 microRNAs, suggesting common underlying mechanisms.

CONCLUSION

Sequencing of well-characterized patient cohorts produced unbiased profiling of the circulating miRNome and identified a unique panel of 11 microRNAs in early radiographic knee OA.

Long-term outcome after resection of non-small cell lung cancer invading the thoracic inlet

BACKGROUND

The aim of this study was to update our previous experience and describe long-term results after resection of non-small-cell lung cancer (NSCLC) invading the thoracic inlet.

METHODS

Patients from a single center undergoing resection of NSCLC invading the thoracic inlet were reviewed with data retrieved retrospectively from their charts.

RESULTS

Sixty-five consecutive patients with a median age of 61 (32-76) years underwent resection of NSCLC invading the thoracic inlet from 1991 to 2011. Tumor location was divided into 5 anatomic zones from anterior to posterior. Fifty-two (80%) patients had induction therapy, mostly with 2 cycles of cisplatin-etoposide and 45 Gy of concurrent irradiation. All patients underwent at least first rib resection. Lobectomy was performed in 60 patients (92%). Twenty-four patients (37%) had vertebral resection. Arterial resections were performed in 7 patients (11%). Postoperative morbidity and mortality were 46% and 6%, respectively. Pathologic response to induction was complete (pCR) (n = 19) or nearly complete (pNR) (n = 12) in 31 patients (48%). Adjuvant treatment was administered in 14 (25%) patients. After a median follow-up of 20 (0-193) months, 34 patients are alive without recurrence. The overall 5-year survival reached 69%. Univariate analysis identified site of tumor within the thoracic inlet (p = 0.050), response to induction (p = 0.004), and presence of adjuvant treatment (p = 0.028) as survival predictors.

CONCLUSIONS

Survival after resection of NSCLC invading the thoracic inlet in highly selected patients reached 69% at 5 years. Tumor location within the thoracic inlet, pathologic response to induction therapy, and adjuvant treatments were significant survival predictors.

Microendoscopic approach to far-lateral lumbar disc herniation

The purpose of this study was to determine the feasibility of performing far-lateral lumbar discectomy by using the microendoscopic discectomy (MED) technique. The authors studied 11 consecutive patients with unilateral, single-level radiculopathy secondary to far-lateral disc herniation. There were eight men and three women, with an average age of 43 years. In all patients magnetic resonance imaging and/or computerized tomography scanning documented far-lateral disc herniations. Six patients experienced motor deficits, nine patients sensory abnormalities, and five depressed reflexes. All patients complained of radicular pain, which failed to improve with conservative care. After induction of epidural anesthesia, single-level, unilateral percutaneous discectomies were performed using the MED technique. Five discectomies were performed at L3-4 and six at L4-5. There were four contained and seven sequestered disc herniations. All surgeries were performed on an outpatient basis. Follow up ranged from for 12 to 27 months. Improvement was shown in all patients postoperatively. Using modified Macnab criteria to assess results of surgery, there were 10 excellent results and one good result. None of the patients experienced residual motor deficits, four had residual decreased sensation, and one still had some degree of nonradicular pain. There were no complications. Although various open techniques exist for the treatment of far-lateral disc herniation, MED is unique in that far-lateral pathological entities can be directly visualized and removed via a 15-mm paramedian incision. The percutaneous approach avoids larger, potentially denervating and destabilizing procedures. The need for general anesthesia can be avoided, and surgery is performed on an outpatient basis, thereby reducing hospital cost and length of stay.

Effect of sex and living arrangement on the timing and outcome of joint replacement surgery

BACKGROUND

Studies have shown that women present for surgery at an older age and with greater dysfunction than do men; however, the explanation for this finding is unclear. We investigated the impact living status (alone or with another person) and sex on the timing and outcomes of hip and knee replacement surgery.

METHODS

We surveyed 1722 patients undergoing primary hip or knee replacement surgery. Relevant covariates including demographic data, body mass index, sex, living status and comorbidities were recorded. We assessed joint pain and functional status before surgery and at 3 months and 1 year after surgery using the Western Ontario McMaster University Osteoarthritis Index (WOMAC) scores for pain and function.

RESULTS

In total, 22.9% (395) of all patients (29.3% of women and 14.1% of men) were living alone at the time of surgery. Compared with patients who lived with another person, those who lived alone were significantly older, had greater comorbidity and reported greater joint pain and dysfunction before surgery and 3 months and 1 year after surgery. Living alone and female sex independently predicted a greater preoperative WOMAC score, and living alone predicted an older age at the time of surgery and a poorer 1-year outcome.

CONCLUSION

Patients who live alone may delay joint replacement surgery until an older age and have greater joint pain and dysfunction than those who live with another person, leading to poorer 1-year outcomes.

Use of osteogenic protein-1 in patients at high risk for spinal pseudarthrosis: a prospective cohort study assessing safety, health-related quality of life, and radiographic fusion. Invited submission from the Joint Section on Disorders of the Spine and Peripheral Nerves, March 2007

OBJECT

The capability of osteogenic protein (OP)-1 to induce bone formation has led to an increasing interest in its use in fusion surgery. This prospective study examines the safety and efficacy of OP-1 use in patients considered to be at a high risk for developing pseudarthrosis following reconstructive spinal surgery.

METHODS

Outcome measures included documentation of adverse events, radiographic evaluation of fusion by an independent musculoskeletal radiologist blinded to treatment, the Oswestry Disability Index (ODI), and the 36-Item Short Form Health Survey (SF-36). The health-related quality of life (HRQOL) assessments (ODI and SF-36) were given at baseline and at 3, 6, 12, 18, and 24 months after the surgical OP-1 implant.

RESULTS

The study consisted of 17 male and 13 female patients, with a mean age of 53 years (range 20-77 years). Fourteen patients underwent operations for cervical disease, and 16 for lumbar disease, with a median postoperative follow-up of 24 months (range 13-46 months). There were significant improvements in the physical health (from 28.7 +/- 1.5 to 34.2 +/- 3; p = 0.025) and mental health (from 43.7 +/- 2 to 47.5 +/- 3.1; p = 0.015) summary scores on the SF-36. The mean postoperative ODI score at 6, 9, 12, and 18 months was significantly lower than the baseline ODI score, after taking into consideration a 10-point measurement error (p = 0.0003, p = 0.003, p = 0.004, and p = 0.032, respectively). At 24 months, however, the differences in ODI scores were no longer significant. Of the 30 patients, 24 (80%) were deemed to have a solid fusion. There were no allergic reactions to OP-1 and no symptomatic postoperative hematomas.

CONCLUSIONS

Our results suggest that the use of OP-1 is safe and may contribute to high fusion rates, as demonstrated by radiographs, reduced levels of disability, and improved HRQOL in patients considered to be at a high risk for developing a nonunion after spinal reconstructive surgery.

Use of osteogenic protein–1 in spinal fusion: literature review and preliminary results in a prospective series of high-risk cases

Object

The safety and effectiveness of osteogenic protein (OP)–1 putty (recombinant human bone morphogenetic protein–7) in promoting fusion in complex spinal cases was studied in nine cases.

Methods

The authors prospectively evaluated nine patients requiring spinal fusion in whom there were medical risk factors that would inhibit osseous fusion. Intraoperatively the OP-1 putty mixed with autologous bone was placed at the fusion site. Outcome measurement instruments were used to provide information on patient demographics, comorbidities, and pain. The Short Form (SF)–36 questionnaire and Oswestry Disability Index (ODI) were administered pre- and postoperatively. All patients underwent routine radiography of the surgery site during follow-up examination.

The age of the five women and four men ranged from 21 to 74 years (mean height 1.6 m, mean weight 76.7 kg). Risk factors included mucopolysaccharide syndrome, adrenal insufficiency, rheumatoid arthritis with chronic corticosteroid use, morbid obesity, and heavy smoking. Surgery, which consisted of five cervical and four lumbar procedures, including intradural surgery in three patients, was uneventful in all cases without perioperative complication. The follow-up period ranged from 1 to 15 months (mean 5.22 months). The ODI score changed from severe disability (mean 46.89) pre-operatively to minimal and moderate disability (mean 34.56) postoperatively. The SF-36 survey showed overall improved mental and physical health scores. Fusion was present in all patients with greater than 3 months follow up.

Conclusions

The OP-1 putty appears to be safe and effective in promoting spinal arthrodesis in patients in whom adverse medical risk factors exist.

Virtual fluoroscopy: computer-assisted fluoroscopic navigation

STUDY DESIGN

In vitro accuracy assessment of a novel virtual fluoroscopy system.

OBJECTIVES

To investigate a new technology combining image-guided surgery with C-arm fluoroscopy.

SUMMARY OF BACKGROUND DATA

Fluoroscopy is a useful and familiar technology to all musculoskeletal surgeons. Its limitations include radiation exposure to the patient and operating team and the need to reposition the fluoroscope repeatedly to obtain surgical guidance in multiple planes.

METHODS

Fluoroscopic images of the lumbar spine of an intact, unembalmed cadaver were obtained, calibrated, and saved to an ). A was used for the sequential insertion of a light-emitting diode-fitted probe into the pedicles of L1-S1 bilaterally. The trajectory of a "virtual tool" corresponding to the tracked tool was overlaid onto the saved fluoroscopic views in real time. Live fluoroscopic images of the inserted pedicle probe were then obtained. Distances between the tips of the virtual and fluoroscopically displayed probes were quantified using the image-guided computer's measurement tool. Trajectory angle differences were measured using a standard goniometer and printed copies of the workstation computer display. The surgeon's radiation exposure was measured using thermolucent dosimeter rings.

RESULTS

Excellent correlation between the virtual fluoroscopic images and live fluoroscopy was observed. Mean probe tip error was 0.97 +/- 0.40 mm. Mean trajectory angle difference between the virtual and fluoroscopically displayed probes was 2.7 degrees +/- 0.6 degrees. The thermolucent dosimeter rings measured no detectable radiation exposure for the surgeon.

CONCLUSIONS

Virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. It enables a single C-arm to provide real-time, multiplanar procedural guidance. It also dramatically reduces radiation exposure to the patient and surgical team by eliminating the need for repetitive fluoroscopic imaging for tool placement.

Accuracy requirements for image-guided spinal pedicle screw placement

STUDY DESIGN

Accuracy requirement analysis for image-guided pedicle screw placement.

OBJECTIVES

To derive theoretical accuracy requirements for image-guided spinal pedicle screw placement.

SUMMARY OF BACKGROUND DATA

Underlying causes of inaccuracy in image-guided surgical systems and methods for quantifying this inaccuracy have been studied. However, accuracy requirements for specific spinal surgical procedures have not been delineated. In particular, the accuracy requirements for image-guided spinal pedicle screw placement have not been previously reported.

METHODS

A geometric model was developed relating spinal pedicle anatomy to accuracy requirements for image-guided surgery. This model was used to derive error tolerances for pedicle screw placement when using clinically relevant screw diameters in the cervical (3.5 mm), thoracic (5.0 mm), and thoracolumbar spine (6.5 mm). The error tolerances were represented as the permissible rotational and translational deviations from the ideal screw trajectory that would avoid pedicle wall perforation. The relevant dimensions of the pedicle model were extracted from existing morphometric data.

RESULTS

As anticipated, accuracy requirements were greatest at spinal levels where the relevant screw diameter approximated the dimensions of the pedicle. These requirements were highest for T5, followed in descending order by T4, T7, T6, T3, T12, L1, T8, T11, C4, L2, C3, T10, C5, T2, T9, C6, L3, C2, T1, C7, L4, and L5. Maximum permissible translational/rotational error tolerances ranged from 0.0 mm/0.0 degrees at T5 to 3.8 mm/12.7 degrees at L5.

CONCLUSIONS

These results, obtained by mathematical analysis, demonstrate that extremely high accuracy is necessary to place pedicle screws at certain levels of the spine without perforating the pedicle wall. These accuracy requirements exceed the accuracy of current image-guided surgical systems, based on clinical utility errors reported in the literature. In actual use, however, these systems have been shown to improve the accuracy of pedicle screw placement. This dichotomy indicates that other factors, such as the surgeon's visual and tactile feedback, may be operative.

Radiation exposure to the spine surgeon during fluoroscopically assisted pedicle screw insertion

STUDY DESIGN

In vitro study to determine occupational radiation exposure during lumbar fluoroscopy.

OBJECTIVES

To assess radiation exposure to the spine surgeon during fluoroscopically assisted thoracolumbar pedicle screw placement.

SUMMARY OF BACKGROUND DATA

Occupational radiation exposure during a variety of fluoroscopically assisted musculoskeletal procedures has been previously evaluated. No prior study has assessed fluoroscopy-related radiation exposure to the spine surgeon.

METHODS

Bilateral pedicle screw placement (T11-S1) was performed in six cadavers using lateral fluoroscopic imaging. Radiation dose rates to the surgeon's neck, torso, and dominant hand were measured with dosimeter badges and thermolucent dosimeter (TLD) rings. Radiation levels were also quantified at various distances from the dorsal lumbar surface using an ion chamber radiation survey meter.

RESULTS

The mean dose rate to the neck was 8.3 mrem/min. The dose rate to the torso was greatest when the surgeon was positioned ipsilateral to the beam source (53.3 mrem/min, compared with 2.2 mrem/min on the contralateral side). The average hand dose rate was 58.2 mrem/min. A significant increase in hand dose rate was associated with placement of screws ipsilateral to the beam source (P = 0.0005) and larger specimens (P = 0.0007). Radiation levels significantly decreased as distance from the beam source and dorsal body surface increased. The greatest levels of radiation were noted on the side where the primary radiograph beam entered the cadaver.

CONCLUSION

Fluoroscopically assisted thoracolumbar pedicle screw placement exposes the spine surgeon to significantly greater radiation levels than other, nonspinal musculoskeletal procedures that involve the use of a fluoroscope. In fact, dose rates are up to 10-12 times greater. Spine surgeons performing fluoroscopically assisted thoracolumbar procedures should monitor their annual radiation exposure. Measures to reduce radiation exposure and surgeon awareness of high-exposure body and hand positions are certainly called for.

Anterior cervical plating reverses load transfer through multilevel strut-grafts

STUDY DESIGN

In vitro biomechanical study using a programmable testing apparatus that replicated physiologic flexion/extension cervical spine motion and loading mechanics.

OBJECTIVE

To determine the influence of anterior plating on multilevel cervical strut-graft mechanics in vitro.

SUMMARY OF BACKGROUND DATA

The addition of anterior instrumentation does not prevent construct failure in multilevel cervical corpectomy.

METHODS

Six fresh human cadaveric cervical spines (C2-T1) were tested in the four following sequential conditions: harvested, C4-C6 corpectomy, strut-grafted, and strut-grafted with an anterior cervical plate. A force-sensing strut-graft was used to measure compression/tension, flexion/extension and lateral bending moments, and axial torsion. Parameters of stiffness, vertebral motion, and strut-graft loads were compared to determine differences between the four spine conditions.

RESULTS

Application of the anterior plate significantly increased the global stiffness (P < 0.01) and decreased the local motion (P < or = 0.01) of the instrumented levels (C3-C7). Flexion of the strut-grafted spine loaded the strut-graft, whereas extension unloaded the strut-graft. With the anterior plate, flexion of the plated spine unloaded the strut-graft. Extension significantly loaded the strut-graft more than similar degrees of flexion in the strut-grafted condition (P = 0.01). Strut-graft loading end limits of 225 N were reached with a mean 7.5 degrees extension in the plated spines.

CONCLUSIONS

Anterior multilevel cervical plating effectively increases stiffness and decreases local cervical motion after corpectomy. However, anterior cervical plating also reverses graft loads and excessively loads the graft in extension, which may promote pistoning and failure of multilevel constructs.

The in vitro effects of instrumentation on multilevel cervical strut-graft mechanics

STUDY DESIGN

Biomechanical study using a programmable testing apparatus that replicated physiologic flexion-extension cervical spine motion, and loading mechanics.

OBJECTIVES

To determine the influence of anterior, posterior, or combined plating on multilevel cervical strut-graft mechanics in vitro.

SUMMARY OF BACKGROUND DATA

The addition of instrumentation does not prevent construct failure in multilevel (more than two levels) cervical corpectomy.

METHODS

Six fresh human cadaveric cervical spines (C2-T1) were tested in six sequential conditions that included harvested (H), C4-6 corpectomy, strut grafted, strut grafted with an anterior cervical plate (SGAP), strut grafted with posterior plates (SGPP), and strut grafted with combined anterior and posterior plates (SGAPP). A customized force-sensing strut graft (FSSG) was used to measure axial compression-tension, flexion-extension and lateral bending moments, and axial torsion. Parameters of stiffness, segmental vertebral motion, and strut-graft loads were compared, to determine differences among the spine conditions.

RESULTS

Flexion of the strut-grafted spine loaded the FSSG, and extension motion unloaded the FSSG. With the anterior plate, flexion of the SGAP spine significantly unloaded the FSSG; extension loaded the FSSG more than flexion of the unplated spine (P = 0.03). The opposite occurred with the posterior plates (SGPP), where flexion of the spine significantly loaded the FSSG (more than the strut grafted spine) and extension unloaded the FSSG (P < 0.03). The combined construct (SGAPP) counteracted the tension band effect of the individual plates and demonstrated significantly less overall FSSG load change than either plate alone (P = 0.03).

CONCLUSIONS

Multilevel cervical instrumentation effectively increases stiffness after corpectomy. However, anterior or posterior plating alone excessively loads the graft with small degrees of motion, which may promote pistoning and failure of multilevel constructs.