Lumbar stability following graded unilateral and bilateral facetectomy: A finite element model study.

BACKGROUND: Excision of excessive amount of facet joint during lumbar discectomy or decompression can cause segmental instability of the lumbar spine. This study was performed to assess the segmental instability, facet joint loading and intradiscal pressure following graded lumbar facetectomy. This biomechanical study was performed using a verified and validated L3-S1 finite element model. METHODS: Nine scenarios were analysed. Intact model as control, 30%, 45%, 60% and complete facet joint excision in unilateral and bilateral setting. The effect of progressive graded facetectomy of L4-L5 on the segmental mobility, facet loading and intradiscal pressure was assessed. FINDINGS: In comparison with control 30% excision of the facet joint mainly caused increase in mediolateral mobility. With 45% excision of the facet joint there was increase in both anteroposterior and mediolateral mobility, this was worse in bilateral and unilateral models respectively. This worsened with larger facet excision scenarios. Facet load increased significantly on extension with excision of 45% & 60% unilaterally and 100% bilaterally. Flexion produced rise in intradiscal pressure in all scenarios. INTERPRETATION: The increased spinal mobility, facet loading and intradiscal pressure with more than 30% facetectomy highlights the importance of preserving the facets during decompression thereby safeguarding accelerated degeneration of these segments and iatrogenic segmental instability. The findings from this study could also potentially explain the correlation between spinal instability, disc degeneration and facet joint arthrosis as noted in clinical studies.

Evidence of Paternal N5, N10 - Methylenetetrahydrofolate Reductase (MTHFR) C677T Gene Polymorphism in Couples with Recurrent Spontaneous Abortions (RSAs) in Kolar District- A South West of India.

INTRODUCTION: Recurrent spontaneous abortion (RSA) is a multifactorial clinical obstetrics complication commonly occurring in pregnancy. Many research studies have noted the mutations such as C677T in N5, N10 - Methylenetetrahydrofolate reductase (MTHFR)gene which is regarded as RSA risk factor. This study was carried out to determine the occurrence of frequency of C677T of the MTHFR gene mutations with RSA. AIM: The purpose of present study is to determine the frequency of MTHFR C677T polymorphisms in couples with recurrent pregnancy loss and the impact of paternal polymorphisms of MTHFR C677T in recurrent pregnancy loss in population of couples living in Kolar district of Karnataka with RSA. DESIGN: A total of 15 couples with a history of two or more unexplained RSA were enrolled as subjects in the study and a total of 15 couples with normal reproductive history, having two or more children and no history of miscarriages were enrolled as controls. MATERIALS AND METHODS: DNA extraction from samples case and control group couples and its quantification by Agarose gel electrophoresis, assessment of DNA purity, MTHFR C 677T gene mutation detection by PCR-RFLP method. STATISTICAL ANALYSIS: Carried out by web based online SPSS tool. RESULTS: The frequency of C677T genotype showed homozygous wild type CC (80%), heterozygous CT type (13.3%) and homozygous mutation TT type (6.67%) observed in males. Similarly from female's homozygous wild type CC (86.6%), heterozygous type (13.3%), and homozygous type mutations TT (0%) was recorded. In couple control groups, we observed homozygous wild type CC (86.6%), heterozygous CT type (13.3%) and homozygous type mutations TT type (0%). CONCLUSION: We noticed a high frequency of MTHFR specifically T allele associated with paternal side.Therefore, the present study indicated the impact of paternal gene polymorphism of MTHFR C677T on screening in couples with recurrent pregnancy loss.

Measurement of thromboxane and prostacyclin in valvulotomized human saphenous veins.

The present study was done to determine the effect of the modified Hall valvulotome technique on endothelial injury by measuring TxB2 and 6-keto PGF1alpha, the stable metabolites of thromboxane and prostacyclin, respectively. It was hypothesized that increased levels of these cyclooxygenase products would be an excellent indicator of vascular endothelial injury in the presence of the modified Hall valvulotome. Eight segments of human distal saphenous veins were obtained, each measuring approximately 4 cm in length, with diameters of approximately 2 to 3 mm. From these original vein segments, two groups of smaller vein segments were examined, with each group consisting of eight segments, each segment measuring 2 cm in length. The first group of vein segments was designated as the control group, and the second group of vessels had a modified Hall valvulotome (2.5 mm size) inserted into each segment to simulate valvulotomy. After this procedure, all vein segments were analyzed for levels of thromboxane and prostacyclin by a standard radioimmunoassay procedure. Results from the present study indicate that the modified Hall valvulotome technique in human saphenous veins does not significantly increase the levels of the cyclooxygenase metabolites thromboxane and prostacyclin relative to control conditions. However, the ratio of TxB2 formation 6-keto PGF1alpha production was increased in the valvulotomized vessel segments, indicating possible platelet release of thromboxane. Therefore, even though there was increased thromboxane production relative to prostacyclin levels in the modified Hall valvulotome technique, it still appears that this type of valvulotomy is relatively noninsulting to the endothelial cell lining.

Endothelial cell injury in the human saphenous vein: a comparative study of two valvulotomes.

Use of valvulotomes in non-reversed venous conduits carries the potential of venous endothelial cell injury. Earlier studies have shown that there is a significant decrease in the number of endothelial cells present in the human saphenous vein when employing the circular (LeMaitre) valvulotome. The present study was performed to evaluate and compare the LeMaitre and modified Hall valvulotome techniques on vascular endothelial cells from human saphenous vein. The results of the present study indicate that while both valvulotomes caused a significant decrease in the number of endothelial cells, the modified Hall instrument was less damaging to the vascular endothelium than the LeMaitre valvulotome. These results suggest that the modified Hall valvulotome technique may be more beneficial in maintaining endothelial cell function when the use of a valvulotome is warranted.

Efficacy of albumin supplementation in the surgical intensive care unit: a prospective, randomized study.

OBJECTIVE: To determine the efficacy of supplemental 25% albumin in reducing morbidity and mortality rates in the surgical intensive care unit (ICU). DESIGN: Prospective, randomized, unblinded clinical study. SETTING: Surgical ICU in a community hospital. PATIENTS: Two hundred nineteen patients with admission circulating albumin concentrations of < 3.0 g/dL (< 30 g/L). The groups were well matched regarding age, sex, Acute Physiology and Chronic Health Evaluation II scores and initial circulating albumin concentrations. INTERVENTIONS: The treatment group (n = 116) received 37.5 g/day of albumin until the circulating albumin concentration increased to > 3.0 g/dL (> 30 g/L). The control group (n = 103) received no supplemental albumin. Both groups received standard nutritional support. MEASUREMENTS AND MAIN RESULTS: The complication rate was 44% in the albumin group vs. 36.9% in the controls (p = .29). The albumin patients had a mortality rate of 10.3% vs. 5.8% in the control group (p = .22). There were no significant differences between the groups in the number of days spent receiving mechanical ventilation or in the tolerance to tube feedings. CONCLUSIONS: Routine supplemental administration of 25% albumin is expensive and offers no apparent outcome advantage and should be abandoned in the treatment of patients in the surgical ICU.

Endothelial cell injury in human saphenous veins following use of a circular valvulotome.

With increasing use of nonreversed saphenous vein as a bypass conduit (either in-situ or translocated) several techniques of valve ablation are used. The present study was designed to assess the extent of endothelial damage caused by a circular blade valvulotome.

Laceration of the left pulmonary artery during removal of a bronchogenic cyst by right thoracotomy.

Major vascular involvement by a bronchogenic cyst is rare; most large cysts cause respiratory symptoms. We present a case in which a large bronchogenic cyst was adherent to the left pulmonary artery. During removal of the cyst by right thoracotomy, the artery lacerated. Repair of the artery in such a situation taxes the surgeon's ingenuity and decision-making process.

Use of the internal mammary vein for central venous access.

We have reported two instances requiring long term central venous access in which the more traditional access sites were no longer available. The use of the internal mammary vein has made it possible to easily obtain central venous access in these patients without thoracotomy. Also, based on the anatomy, we believe this to be superior to the intercostal venous approach, since the passage of the catheter is more direct, thus, avoiding the acute azygous arch angle and cumbersome positioning.

Nerve-sparing dissection as alternative to anesthesia of carotid sinus nerve in preparation for carotid endarterectomy.

This prospective randomized study was undertaken to determine intraoperatively the hemodynamic effects of local anesthesia of the carotid sinus nerve during carotid dissection in preparation for endarterectomy. Twenty carotid endarterectomy patients were divided into 2 groups: a control group of 10 patients, in whom ordinary saline solution was infiltrated into the carotid bifurcation; and a study group of 10 patients, in whom 5 mL of 2% lidocaine hydrochloride was infiltrated. To determine whether a nerve-sparing dissection might in itself be adequate to prevent the perioperative hemodynamic instability associated with carotid endarterectomy, we took scrupulous care in all patients to avoid injuring the carotid sinus nerve. After we had established baseline values for heart rate and blood pressure in each patient, we recorded heart rate and blood pressure again intraoperatively, every 2 minutes during a 10-minute period. Because the series was small, an analysis of variance showed no statistically significant changes in these values during carotid dissection in either group. However, intraoperative increases in systolic pressure (p < 0.0064) and mean pressure (p < 0.0028) were greater in the lidocaine group. Neither group experienced any deaths, or any neurologic or hemodynamic sequelae during 48 hours of postoperative observation. We conclude that local anesthetic injection of the carotid sinus nerve before carotid dissection and endarterectomy is unnecessary when nerve-sparing dissection is performed; and we conclude further that such injection might actually be deleterious to intraoperative systolic and mean blood pressures.