Why should the anesthesiologist evaluate nutritional status?

BACKGROUND: The anesthesiologist's involvement in perioperative medicine has significantly changed. In order to identify patients at risks of perioperative complications, the anesthesiologist has to consider, amongst others, screening and management of undernutrition. For this purpose knowledge of prevalence and risk factors, along with screening tools and guidelines for an adapted nutritional management and outcomes of renutrition are mandatory. The present review intends to provide these tools to the Anesthesiologists. METHOD: We conduct a literature review in Pubmed, Direct Science and Cochrane Library without limit of time related to undernutrition in the perioperative period. RESULTS: Undernutrition is common in surgical patients. Undernutrition is associated with an increase of morbidity, mortality, length of hospital stay and costs. Undernutrition could probably be detected during the anesthetic consultation with simple and rapid tests, such as SNAQ, MST, MUST and NRS-2002. Nevertheless, further studies are needed to validate such tests in surgical patients. Waiting for these results, we prefer MUST. The implementation of nutritional support recommendations would reduce postoperative complications. CONCLUSION: The anesthesiologist could play an important role in undernutrition screening and its management in order to reduce perioperative morbidity.

In vivo optical spectroscopy monitoring in a new model of muscular compartment syndrome.

BACKGROUND: Muscular compartment syndrome (MCS) is a rare but serious postoperative complication. In vivo optical spectroscopy (INVOS) monitors continuously and non-invasively regional oxygen saturation (rSO(2)), and could predict the development of MCS. METHODS: In 10 healthy volunteers, we inflated a tourniquet to the mean arterial pressure to produce slight venous congestion and arterial hypoperfusion. Comparisons were made between the relative reduction in rSO(2) with baseline (deltaINVOS) and the time to observe motor nerve block (with non-invasive electromyography). Neurological symptoms, pain, and invasive intracompartmental pressure (ICP) were assessed. RESULTS: In the eight volunteers completing the protocol, we observed a profound motor nerve conduction block, immediately reversible. Baseline values were: [mean (sd)] INVOS: 73.3 (8.9)% and ICP: 16.9 (8.6) mm Hg. At the time of the block, values were: INVOS: 46.4 (10.9)%, deltaINVOS: 28.7 (10.6)%, and ICP: 70.0 (5.5) mm Hg. The time to reach the block was 33.0 (10.9) min, and to a deltaINVOS>10%: 27.4 (10.4) min. Receiver-operating characteristic curves demonstrated a similar accuracy of ICP and INVOS to predict the occurrence of the block. Twenty minutes with a deltaINVOS>10% or ICP>30 mm Hg were associated with a sensitivity and a specificity of 95% and 70%; or 91% and 65%, respectively. CONCLUSIONS: We have developed a model of acute immediately reversible MCS. Monitoring using the INVOS technology is as accurate as measurement of ICP, and could be a useful tool to prevent development of intraoperative MCS.

Percutaneous CT guided resection of osteoid osteoma of the tibial plafond.

Osteoid osteomas of the foot and ankle are relatively rare and notoriously difficult to diagnose. Juxta-articular osteoid osteomas are more difficult to treat and often have a significant delay in diagnosis. We report a case of a juxta-articular osteoid osteoma of the tibial plafond. Once the diagnosis was made, excisional biopsy was performed percutaneously under computed tomography (CT) guidance as an outpatient in the radiology suite. The patient had complete resolution of symptoms and remains pain free at two years follow-up. CT guided resection can be a lower morbidity and more cost effective technique to treat this lesion than traditional methods.

Imaging of infections and inflammatory conditions of the spine.

The lack of specific clinical, laboratory, and radiologic findings in patients with a disease as potentially debilitating as infectious spondylitis is challenging. Biopsy will frequently need to be performed but is itself often nondiagnostic and is not without risk. Therefore, identification of findings, often subtle, that strongly favor other entities in the differential may be of just as much clinical import as identifying findings worrisome for infection, particularly in the subset of patients who otherwise are felt unlikely to have a disc space infection. Radiography and magnetic resonance (MR) imaging are complementary imaging techniques and both should be performed. The pertinent vascular anatomy of the spine; the epidemiologic, microbiologic, and clinical features of infectious spondylitis; and the role of imaging are reviewed in this article. Particular emphasis is placed on imaging differentiation of the various discovertebral disease processes.

The pathology of total joint arthroplasty.II. Mechanisms of implant failure.

Although the clinical results of total joint arthroplasty are usually excellent, some implants develop loosening and require revision. Implants usually fail by a combination of mechanisms, but different basic designs tend to show different dominant mechanisms of failure. Infection causes failure of about 1-5% of cases of primary arthroplasty. Clues to the presence of infection include clinical signs, a periosteal reaction, a positive culture of aspirated joint fluid, and acute inflammation identified in tissue around the implant. There are several different mechanisms and modes of implant wear, and perhaps the most important cause of aseptic loosening is an inflammatory reaction to particles of wear debris. Abrasive, adhesive, and fatigue wear of polyethylene, metal and bone cement produces debris particles that induce bone resorption and implant loosening. Particles can cause linear, geographic, or erosive patterns of bone resorption (osteolysis), the distributions of which are influenced by the implant design. Micromotion of implants that did not achieve adequate initial fixation is another important mechanism of loosening. Fatigue failure at the bone/cement and bone/implant interface may cause aseptic loosening, and may be especially important for implants with relatively smooth surfaces. Stress shielding can influence local bone density, but is rarely an isolated cause of implant loosening. Elevated hydrodynamic pressure has been associated with bone resorption in the absence of implants, and may also play a role in implant loosening.

MR imaging of spinal infections.

In the appropriate clinical situation, MR imaging is a powerful tool in the diagnosis of spinal infection. Imaging of spinal infections requires the use of a combination of T1-weighted and T2-weighted or STIR sequences. Contrast enhancement is useful and helps to define paraspinal and epidural disease. Knowledge of potential pitfalls with MR imaging and of normal marrow conversion is required. With these points in mind, MR imaging will be beneficial in the care of patients with spinal infections.

The pathology of total joint arthroplasty. I. Mechanisms of implant fixation.

The clinical results of total joint arthroplasty are usually excellent, but surgeons, radiologists, and pathologists are often called upon to evaluate, in one way or another, the stability of the implants. These evaluations are aided by an understanding of the basic pathophysiology of total joint arthroplasty. The first part of this two-part review, will summarize the mechanisms whereby total joint implants achieve fixation. The second part will describe and illustrate the most important mechanisms of implant loosening. The "gold standard" for hip and knee arthroplasty is to use polymethylmethacrylate bone cement to anchor the implant to bone, but the optimal surface texture of cemented implants is controversial. Some surgeons advocate a rough implant texture to facilitate bonding between implant and cement; other surgeons prefer a smooth, polished implant to minimize abrasion of cement. Implant loosening can be initiated by particles of cement generated at either the implant/cement, or cement/bone interface. Uncemented implants with porous metal surfaces achieve a variable amount of bone ingrowth, but some designs have excellent clinical results. Maximal bone ingrowth usually occurs along surfaces that are relatively close to cortical bone. Implants with bioactive coatings, such as hydroxyapatite achieve rapid bone apposition. The amount of bone that persists on uncemented implants long-term is determined by many variables, inlcuding the quality of the coating, the overall implant design, and factors that influence local bone remodeling.

Selenium-based digital radiography versus conventional film-screen radiography of the hands and feet: a subjective comparison.

OBJECTIVE: The purpose of this study was to subjectively compare the visibility of normal anatomy of the hands and feet using selenium-based digital radiography versus conventional film-screen (100-speed) radiography. SUBJECTS AND METHODS: Digital and film-screen images of the hands and feet of 24 patients were obtained without an antiscatter grid using identical X-ray exposure. Each pair of images was evaluated independently by five experienced radiologists for visibility of normal anatomy using a six-point rating scale. Soft tissues, cortical bone, and trabeculae were evaluated. For each observer, "equivalence" was defined as a mean difference in image quality of less than 1 unit on the 0-5 scale used in the study. Paired t tests were also performed to determine whether the average visibility rating of one technique was statistically superior to that of the other at a .05 level of significance for each observer and at each anatomic landmark. RESULTS: In all categories, selenium-based digital images were rated equivalent to film-screen images by the five observers. Using the sum of the nine landmarks, four of the five observers rated the quality of selenium-based digital images superior to that of film-screen images. CONCLUSION: Subjective visibility of normal anatomy of the hands and feet using selenium-based digital radiography was similar to that achieved using conventional film-screen radiography.

Imaging modalities for study of the distal ulnar region.

Judicious use of diagnostic imaging maximizes the diagnostic capabilities of the surgeon treating the distal radio-ulnar joint (DRUJ). A good clinical history and clinical examination are necessary to direct the selection of appropriate imaging studies. Plain radiographs are almost always the first imaging examination. More advanced imaging techniques are costly and may provide only limited information. This article discusses imaging modalities useful for assessment of the DRUJ and the area around it.

The Bennett lesion of the shoulder.

In this article we review the imaging features and significance of the Bennett lesion of the shoulder. Standard radiographic, computed arthrotomographic, and MR findings in three baseball pitchers diagnosed with Bennett lesions of the shoulder are discussed. A crescent-shaped region of mineralization at the posteroinferior aspect of the glenoid rim, consistent with a Bennett lesion, arises at the insertion of the posterior joint capsule. The diagnosis of this lesion, typically in baseball pitchers, should raise suspicion for associated labral and rotator cuff abnormalities.

Acute calcific tendinitis of the hip: case report with magnetic resonance imaging findings.

The clinical presentation of acute calcific tendinitis can be quite dramatic. This report describes a patient with this entity who had calcification in an unusual area, accompanied by abnormalities seen on radiography and magnetic resonance imaging. Clinical aspects of acute calcific tendinitis are also reviewed. With recognition of this entity, treatment can be initiated promptly, with dramatic resolution.

MR imaging of vertebral osteomyelitis revisited.

OBJECTIVE: The purpose of this study was to reevaluate previously reported MR imaging findings for vertebral osteomyelitis that include decreased signal intensity in the disk and adjacent vertebral bodies on T1-weighted images, increased signal intensity in the disk and adjacent vertebral bodies on T2-weighted images, loss of endplate definition on T1-weighted images, and contrast enhancement of the disk, adjacent vertebral bodies, and involved paraspinal and epidural soft tissues. MATERIALS AND METHODS: Medical records, radiographs, and MR scans of 37 patients with vertebral osteomyelitis with 41 levels of involvement were reviewed for agreement with reported MR imaging findings. RESULTS: Ninety-five percent of the levels (39/41) showed decreased vertebral body signal intensity on T1-weighted images; 95% (39/41) had loss of endplate definition; 95% (37/39) had increased disk signal intensity on T2-weighted images; and 56% (22/39) had increased vertebral body signal intensity on T2-weighted images. Eighty-five percent of the levels (35/41) and 84% of patients (31/37) had both signal intensity changes of the vertebral body on T1-weighted images and signal intensity changes of the disk on T1-and T2-weighted images. Only 46% of the levels (19/41) and 49% of patients (18/37) had both vertebral body and disk changes on T1- and T2-weighted images. Contrast enhancement of the disk and vertebral body was seen in 94% of patients (17/18). Ring enhancement of paraspinal and epidural processes was found to correlate at surgery with abscess, and homogeneous enhancement was found to correlate with phlegmon. CONCLUSION: Hypointense signal intensity in the vertebral body on T1-weighted images, abnormal disk signal intensity on both T1- and T2-weighted images, and contrast enhancement are the findings that indicate spinal infection most reliably.