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Maastricht, Netherlands

Balthasar A.,Maastricht University | Desjardins A.E.,Philips | Van Der Voort M.,Philips | Lucassen G.W.,Philips | And 6 more authors.
Regional Anesthesia and Pain Medicine | Year: 2012

Background and Objectives: Complications resulting from vascular penetration during nerve blocks are rare but potentially devastating events that can occur despite meticulous technique. In this in vivo human pilot study, we investigated the potential for detecting vascular penetration with optical reflectance spectroscopy during blocks of the sympathetic chain and the communicating ramus at lumbar levels. Methods: A custom-designed needle stylet with integrated optical fibers was used in combination with a commercial needle shaft. The needle stylet was connected to a console that delivered broadband light to tissue and spectrally resolved light that was scattered near the stylet tip. A total of 18 insertions were performed on 10 patients; testing for vascular penetration at the nerve target region was performed with aspiration and with radio-opaque contrast injections, visualized fluoroscopically. Optical absorption by hemoglobin was quantified with a blood parameter that was calculated from each spectrum. The blood parameter provided a measure of the difference between spectra acquired from the nerve target region and reference spectra acquired from blood extracted from a volunteer. Results: In 2 insertions, vascular penetration was detected. Pronounced optical absorption by hemoglobin was observed to be associated with both of these events and absent in all other cases. The difference between the blood parameters obtained when vascular penetration was detected, and all other blood parameters were statistically significant (P = 0.006), with a diagnostic odds ratio of 35.4 (confidence interval, 2.21 to ∞). Conclusions: The results from this study suggest that optical spectroscopy has the potential to detect intravascular needle placement, which may in turn increase the safety of nerve blocks. Copyright © 2012 by American Society of Regional Anesthesia and Pain Medicine. Source


Brynolf M.,Karolinska University Hospital | Sommer M.,Academic Hospital of Maastricht | Desjardins A.E.,Philips | Van Der Voort M.,Philips | And 8 more authors.
Regional Anesthesia and Pain Medicine | Year: 2011

BACKGROUND AND OBJECTIVES: Accurate identification of nerves is critical to ensure safe and effective delivery of regional anesthesia during peripheral nerve blocks. Nerve stimulation is commonly used, but it is not perfect. Even when nerve stimulation is performed in conjunction with ultrasound guidance, determining when the needle tip is at the nerve target region can be challenging. In this in vivo pilot study, we investigated whether close proximity to the brachial plexus and penetration of the axillary artery can be identified with optical reflectance spectroscopy, using a custom needle stylet with integrated optical fibers. METHODS: Ultrasound-guided insertions to place the needle tip near the brachial plexus at the axillary level were performed at multiple locations in 2 swine, with the stylet positioned in the cannula of a 20-gauge stimulation needle. During each insertion, optical reflectance spectra were acquired with the needle tip in skeletal muscle, at the surface of muscle fascia, and at the nerve target region; confirmation of the final needle position was provided by nerve stimulation. In addition, an insertion to the lumen of the axillary artery was performed in a third swine. Differences in the spectra were quantified with lipid and hemoglobin parameters that provide contrast for optical absorption by the respective chromophores. RESULTS: The transition of the needle tip from skeletal muscle to the nerve target region was associated with higher lipid parameter values (P < 0.001) and lower hemoglobin parameter values (P < 0.001). The transition of the needle tip from muscle fascia to the nerve target region was associated with higher lipid parameter values (P = 0.001). Intraluminal access of the axillary artery was associated with an elevated hemoglobin parameter. CONCLUSIONS: Spectroscopic information obtained with the optical needle is distinct from nerve stimulation and complementary to ultrasound imaging, and it could potentially allow for reliable identification of the injection site during peripheral nerve blocks. Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine. Source


Van Der Hagen S.J.,Academic Hospital of Maastricht | Baeten C.G.,Academic Hospital of Maastricht | Soeters P.B.,Academic Hospital of Maastricht | Van Gemert W.G.,Academic Hospital of Maastricht
Gastroenterology Research and Practice | Year: 2011

Background. In this prospective randomised study, the staged mucosal advancement flap is compared with staged fibrin sealant application in the treatment of perianal fistulas. Methods. All patients with high complex cryptoglandular fistulas were randomised to closure of the internal opening by a mucosal advancement flap (MF) or injection with fibrin sealant (FS) after treatment with setons. Recurrence rate and incontinence disorders were explored. Results. The MF group (5 females and 10 males) with a median age of 51 years and a median followup of 52 months. The FS group (4 females and 11 males) with a median age of 45 years and a median followup of 49 months. Three (20) patients of the MF group had a recurrent fistula compared to 9 (60) of the FS group (P=0.03). No new continence disorders developed. Conclusion. Staged FS injection has a much lower success rate compared to MF. © 2011 S. J. van der Hagen et al. Source

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