Posterior Vertebral Column Resection for VATER/VACTERL Associated Spinal Deformity: A Case Report

The VATER/VACTERL association is a syndrome notable for congenital vertebral malformations, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, and renal or limb malformations. Vertebral malformations may include the entire spectrum of congenital spinal deformities, including kyphosis, as was seen in this case. A 14-year-old girl presented to our institution with severe rigid sagittal deformity in the thoracolumbar spine that had recurred following three prior spinal fusion surgeries: the first posterior only, the second anterior and posterior, and the third a posterior only proximal extension. These surgeries were performed to control progressive kyphosis from a complex failure of segmentation that resulted in a 66° kyphosis from T11 to L3 by the time she was 9 years old. Our evaluation revealed solid arthrodesis from the most recent procedures with resultant sagittal imbalance, and surgical options to restore balance included anterior and posterior revision spinal fusion with osteotomies, multiple posterior extension osteotomies with circumferential spine fusion, and posterior vertebral column resection with circumferential spine fusion. She was advised that multiple posterior extension osteotomies would likely be insufficient to restore sagittal balance in the setting of solid arthrodesis from anterior and posterior surgery, and that the posterior-only vertebral column resection would provide results equivalent to revision anterior and posterior surgery, without the morbidity of the anterior approach. She successfully underwent posterior vertebrectomy and circumferential spinal fusion with instrumentation and is doing well 2 years postoperatively. Severe rigid sagittal deformity can be effectively managed with a posterior-only surgical approach, vertebrectomy, and circumferential spinal fusion with instrumentation. An erratum to this article can be found at     

Lymphatic Drainage of the Peritoneal Space: A Pattern Dependent on Bowel Lymphatics

Background Understanding lymph drainage patterns of the peritoneum could assist in staging and treatment of gastrointestinal and ovarian malignancies. Sentinel lymph nodes (SLNs) have been identified for solid organs and the pleural space. Our purpose was to determine whether the peritoneal space has a predictable lymph node drainage pattern. Methods Rats received intraperitoneal injections of near-infrared (NIR) fluorescent tracers: namely, quantum dots (designed for retention in SLNs) or human serum albumin conjugated with IRDye800 (HSA800; designed for lymphatic flow beyond the SLN). A custom imaging system detected NIR fluorescence at 10 and 20 minutes and 1, 4, and 24 hours after injection. To determine the contribution of viscera to peritoneal lymphatic flow, additional cohorts received bowel resection before NIR tracer injection. Associations with appropriate controls were assessed with the χ² test. Results Quantum dots drained to the celiac, superior mesenteric, and periportal lymph node groups. HSA800 drained to these same groups at early time points but continued flowing to the mediastinal lymph nodes via the thoracic duct. After bowel resection, both tracers were found in the thoracic, not abdominal, lymph node groups. Additionally, HSA800 was no longer found in the thoracic duct but in the anterior chest wall and diaphragmatic lymphatics. Conclusions The peritoneal space drains to the celiac, superior mesenteric, and periportal lymph node groups first. Lymph continues via the thoracic duct to the mediastinal lymph nodes. Bowel lymphatics are a key determinant of peritoneal lymph flow, because bowel resection shifts lymph flow directly to the intrathoracic lymph nodes via chest wall lymphatics. Dr. Parungo was the recipient of an award at the SSO meeting.     

Backside Wear in Modern Total Knee Designs

Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II® (IB II®), Optetrak®, and Advance®. A random sample of 71 inserts were obtained from our institution’s retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0–10%, 2 = 10–50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance® and IB II® polyethylene inserts showed significantly higher scores for backside wear than the Optetrak® inserts. All IB II® and Advance® implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak® implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.Key words: polyethylene, wear, knee, backside, back surface, locking mechanism     

Akt‐mediated mechanotransduction in murine fibroblasts during hypertrophic scar formation

Although numerous factors are implicated in skin fibrosis, the exact pathophysiology of hypertrophic scarring remains unknown. We recently demonstrated that mechanical force initiates hypertrophic scar formation in a murine model, potentially enhancing cellular survival through Akt. Here, we specifically examined Akt‐mediated mechanotransduction in fibroblasts using both strain culture systems and our murine scar model. In vitro, static strain increased fibroblast motility, an effect blocked by wortmannin (a phosphoinositide‐3‐kinase/Akt inhibitor). We also demonstrated that high‐frequency cyclic strain was more effective at inducing Akt phosphorylation than low frequency or static strain. In vivo, Akt phosphorylation was induced by mechanical loading of dermal fibroblasts in both unwounded and wounded murine skin. Mechanically loaded scars also exhibited strong expression of α‐smooth muscle actin, a putative marker of pathologic scar formation. In vivo inhibition of Akt increased apoptosis but did not significantly abrogate hypertrophic scar development. These data suggest that although Akt signaling is activated in fibroblasts during mechanical loading of skin, this is not the critical pathway in hypertrophic scar formation. Future studies are needed to fully elucidate the critical mechanotransduction components and pathways which activate skin fibrosis.     

Diffuse idiopathic skeletal hyperostosis of the cervical spine: an underestimated cause of dysphagia and airway obstruction

Background context

Diffuse idiopathic skeletal hyperostosis (DISH) is a common but underdiagnosed condition relating to ossification of spinal ligaments that can cause compression of the esophagus and trachea. According to case reports, dysphagia or airway obstruction resulting from DISH is a rare occurrence.

Purpose

This study was intended to identify all published cases of dysphagia and/or airway obstruction resulting from DISH to increase the epidemiologic/clinical knowledge of these related conditions.

Study design

A systematic review of the literature was performed.

Methods

The articles resulting from the systematic PubMed/EMBASE search of the literature were closely read, and predefined parameters were scored.

Results

The search yielded a total of 118 articles (95 case reports and 23 case series) describing 204 patients with dysphagia and/or airway obstruction resulting from DISH. The number of cases demonstrated a steady increase from 1980 to 2009. This might be a real effect not ascribable to publication bias or expansion of the medical literature alone.

Conclusions

Diffuse idiopathic skeletal hyperostosis as a cause of dysphagia and/or airway obstruction may be an increasing and underappreciated phenomenon. Diffuse idiopathic skeletal hyperostosis should be included in the differential diagnosis of dysphagia and airway obstruction.