Experimental Study of the Course of Threshold Current,Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

BackgroundTranscranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances.ObjectiveThreshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the cerebral cortex.Patients and MethodsData of 10 patients (6f, 53 ± 11 years) were analyzed. Motor evoked potentials were elicited by constant current stimulation with corkscrew type electrodes (CS) at C3 and C4 in line with standard transcranial electric stimulation. A monopolar anodal ball tip shaped probe was used for all other measurements being performed at the level of the skin, dura and cortex, as well as within the skull by stepwise performed burr holes close to C3 resp. C4.ResultsAverage stimulation intensity, corresponding voltage and impedance for muscle MEPs at current motor threshold (CMT) were recorded: CS 54 ± 23 mA (mean ± SD), 38 ± 21 V, 686 ± 146 Ω; with the monopolar probe on skin 55 ± 28 mA, 100 ± 44 V, 1911 ± 683 Ω and scalp 59 ± 32 mA, 56 ± 28 V, 1010 ± 402 Ω; within the skull bone: outer compact layer 33 ± 23 mA, 91 ± 53 V, 3734 ± 2793 Ω; spongiform layer 33 ± 23 mA, 70 ± 44 V, 2347 ± 1327 Ω; inner compact layer (ICL) 28 ± 19 mA, 48 ± 23 V, 2103 ± 1498 Ω; on dura 25 ± 12 mA, 17 ± 12 V, 643 ± 244 Ω and cortex 14 ± 6 mA, 11 ± 5 V, 859 ± 300 Ω. CMTs were only significantly different for CS (P = 0.02) and for the monopolar probe between the cortex and ICL (P = 0.03), scalp (P = 0.01) or skin (P = 0.01) and between ICL and CS (P ≤ 0.01) or skin (P ≤ 0.01).ConclusionThe mean stimulation current of the CMT along the extracranial to intracranial anodal trajectory followed a stepwise reduction. VMT was strongly dependent on electrode impedance. CMT within the skull layers was noted to have relative strong shunting currents in scalp layers.     

Strictureplasty in Crohn’s Disease: Short and Long-Term Follow-Up

Strictureplasty for obstructive Crohn’s disease is still controversial because lesions are left in place and the suture is performed on a diseased bowel. Many surgeons prefer to perform bowel resection, hoping for fewer complications and a lower recurrence rate. In this paper, the authors report their strictureplasty experience. They performed a systematic retrospective review of the patients suffering from Crohn’s disease who underwent strictureplasties during a 10-year period in the abdominal surgery department of the University Hospital of Liège Sart Tilman, and studied the short-and long-term clinical results of 68 strictureplasties performed in 18 patients. Median follow-up was 63 months (range 12 to 144). Mortality was 0% and septic morbidity was 11% (one wound abscess and one leakage). Among the 16 patients available for the latest follow-up, symptomatic stenotic recurrence had to be medically treated in hospital for 4 patients (25%) with a recurrence delay range of 19 to 49 months. Stenosis recurrence needed re-intervention in one patient 48 months after surgery: stenosis occurred at a distance from the corrected site. These results confirmed that strictureplasty is a safe and efficient procedure in selected patients undergoing surgery for obstructive Crohn’s disease.     

The incidence and natural course of occult inguinal hernias during TAPP repair

Background

One of the proposed advantages of laparoscopic inguinal hernia repair is complimentary inspection of the contralateral side and possible detection of occult hernias. Incidence of occult contralateral hernias is as high as 50 %. The natural course of such occult defects is unknown and therefore operative rationale is lacking. This study was designed to analyze the incidence of occult contralateral inguinal hernias and its natural course.

Methods

A total of 1,681 patients were diagnosed preoperatively with unilateral inguinal hernia. None of these patients had complaints of the contralateral side preoperatively. All patients underwent laparoscopic inguinal hernia transabdominal preperitoneal (TAPP) repair. Operative details were analyzed retrospectively. Patients with occult contralateral defects were identified and tracked. Patients with an evident occult hernia received immediate repair. Patients with a smaller beginning or incipient hernia were followed.

Results

In 218 (13 %) patients, an occult hernia was found at the contralateral side during preoperative exploration. In 129 (8 %) patients, an occult true hernia was found. In 89 (5 %) patients, an occult incipient hernia was found. An incipient hernia was defined as a beginning hernia. All patients with an incipient hernia were followed. The mean follow-up was 112 (range 16–218) months. Twenty-eight (32 %) patients were lost to follow-up. In the 61 remaining patients, 13 (21 %) occult incipient hernias became symptomatic requiring repair. The mean time between primary repair and development of a symptomatic hernia on the contralateral side was 88 (range 24–210) months.

Conclusions

This study shows that the incidence of occult contralateral hernias is 13 % during TAPP repair of unilateral diagnosed inguinal hernias. In 5 % of the cases, the occult hernia consisted of a beginning hernia. Eventually, one of five will become symptomatic and require repair. These outcomes support immediate repair of occult defects, no matter its size.     

Evidence for an Exaggerated Postprandial Lipemia in Chronic Paraplegia

Abstract

Background/Objective: Excessive delay in triglyceride (TG) metabolism after ingestion of dietary fatrepresents a significant cardiovascular disease (CVD) risk. The objective of this study was to compare thepostprandial lipemic responses of individuals with paraplegia with those of healthy nondisabled individuals.

Methods: The ability of 3 recreationally active individuals with paraplegia having normal fasting TG(mean= 103 mg/dl) to metabolize TG after ingestion of a high-fat test meal was compared with apreviously published cohort of 21 recreationally active individuals without paraplegia (TG mean= 86 mg/dl)who underwent identical testing. The subjects with paraplegia had venous blood taken under fastingconditions, and then ingested a milkshake containing premium ice cream blended with heavy whippingcream(~ 92% of calories from fat). Additional blood samples were obtained at 2, 4, and 6 hours afteringestion. The area under the curve (AUC) for TG clearance for both subject groups was measured with anarea planimeter.

Results: TG uptake for both groups was almost identical for the first 2 hours after ingestion. At 4 and 6 hoursafter ingestion, the TG levels were 50 and 35 mg/dl higher, respectively, in subjects with paraplegia than innondisabled subjects. When corrected for small baseline differences in TG concentrations (16 mg/dl), theAUC was 46.5% greater for the group with paraplegia than in the nondisabled group. A near mirrorassociation across time was observed between postprandial serum high-density lipoprotein cholesterol(HDL-C) and TG levels in subjects with paraplegia.

Conclusion: This case series finds an exaggerated postprandial lipemia (PPL) in persons with paraplegiawith normal fasting TGs. This finding is the first evidence, in a small population, of an unreported potentialCVD risk in persons with paraplegia.