Regenerative medicine as applied to general surgery

The present review illustrates the state of the art of regenerative medicine (RM) as applied to surgical diseases and demonstrates that this field has the potential to address some of the unmet needs in surgery. RM is a multidisciplinary field whose purpose is to regenerate in vivo or ex vivo human cells, tissues, or organs to restore or establish normal function through exploitation of the potential to regenerate, which is intrinsic to human cells, tissues, and organs. RM uses cells and/or specially designed biomaterials to reach its goals and RM-based therapies are already in use in several clinical trials in most fields of surgery. The main challenges for investigators are threefold: Creation of an appropriate microenvironment ex vivo that is able to sustain cell physiology and function in order to generate the desired cells or body parts; identification and appropriate manipulation of cells that have the potential to generate parenchymal, stromal and vascular components on demand, both in vivo and ex vivo; and production of smart materials that are able to drive cell fate.     

A unique presentation of a standard type C esophageal atresia in a very low-birth-weight neonate

Neonates with esophageal atresia and tracheoesophageal fistula usually present with inability to swallow immediately after birth often associated with respiratory distress. This is an unusual presentation of a very low-birth-weight neonate with a type C tracheoesophageal fistula that was fed for the first 4 days of life through an unintentional tracheogastric tube without incident.     

Effect of corticosteroids on arginine vasopressin after pediatric cardiac surgery

Introduction

Arginine vasopressin’s (AVP) efficacy in the treatment of refractory hypotension is, in part, dependent upon preinfusion endogenous AVP concentration. Corticosteroids, also commonly used to treat refractory hypotension, have been shown to suppress endogenous AVP release. We aimed to determine if corticosteroids affect endogenous AVP concentrations in children recovering from cardiac surgery.

Materials and methods

We reviewed the records of children who underwent cardiac surgery between January 2008 and January 2009 and had AVP concentrations available as part of a prior prospective study. Doses of hydrocortisone, methylprednisolone, and dexamethasone administered within the first 48 hours after cardiopulmonary bypass were quantitated. Multivariable linear regression was performed to determine if corticosteroids had a significant effect on 48-hour plasma AVP concentration.

Results

Sixty-nine children with plasma AVP concentrations available were reviewed, 34 (49%) of which received corticosteroids within 48 hours after cardiopulmonary bypass. On multivariable regression, greater number of corticosteroid doses but not cumulative corticosteroid dosage was significantly associated with low 48-hour AVP concentration (β = − 4.0; 95% confidence intervals, − 6.5 to − 1.4).

Conclusions

Children who receive multiple doses of corticosteroids after cardiac surgery, regardless of potency, are likely to have low endogenous AVP concentrations. Children who remain unstable despite corticosteroids may respond favorably to exogenous AVP therapy.     

Individual responses to alignment perturbations in socket reaction moments while walking in transtibial prostheses

Background

The alignment of transtibial prostheses has a systematic effect on the mean socket reaction moments in amputees. However, understanding their individual differences in response to alignment perturbations is also important for prosthetists to fully utilize the socket reaction moments for dynamic alignment in each unique patient. The aim of this study was to investigate individual responses to alignment perturbations in transtibial prostheses with solid-ankle-cushion-heel feet.

Methods

A custom instrumented prosthesis alignment component was used to measure the socket reaction moments while walking in 11 amputees with transtibial prostheses under 17 alignment conditions, including 3° and 6° of flexion, extension, abduction, and adduction of the socket, 5 mm and 10 mm of anterior, posterior, lateral, and medial translation of the socket, and an initial baseline alignment. Coronal moments at 30% of stance and maximum sagittal moments were extracted for comparisons from each amputee.

Findings

In the coronal plane, varus moment at 30% of stance was generally reduced by adduction or medial translation of the socket in all the amputees. In the sagittal plane, extension moment was generally increased by posterior translation or flexion of the socket; however, this was not necessarily the case for all the amputees.

Interpretations

Individual responses to alignment perturbations are not always consistent, and prosthetists would need to be aware of this variance when addressing individual socket reaction moments during dynamic alignment in clinical setting.