Medial placement of trapezoid tunnel leads to higher reduction loss in acute acromioclavicular joint dislocation treated with anatomic coracoclavicular fixation.

Aim: To analyze the association between clavicular tunnel positioning and postoperative reduction loss in patients with acute acromioclavicular (AC) joint dislocation treated with anatomic coracoclavicular (CC) fixation using double clavicular tunnels. Methods: A retrospective review of patients with AC joint dislocation, treated with anatomic CC fixation using double clavicular tunnels, was conducted. Patients with pre-operative, immediate post-operative, and final follow-up Zanca-view X-rays were included. On each X-ray, the obtained measures included: distance from lateral border of clavicle to trapezoid and conoid tunnels, distance between tunnels, clavicle length, and CC distance of affected and un-affected sides. Loss of reduction was calculated as CC distance difference between immediate and final post-operative X-rays. Association between reduction loss and tunnel positioning was analyzed. Results: Conoid, trapezoid and tunnel ratios were 24% ± 4, 15% ± 3, and 9% ± 2, respectively. Significant reduction loss was seen in 21(45.7%) patients. Significantly higher probabilities of reduction loss were associated with trapezoid tunnels placed medial to 24 mm (30.8% vs 65.0%, OR 4.2 (IC95%: 1.2-14.4), p: 0.024) or 15% of the clavicle length (32.1% vs 66.7%, OR 4.2 (IC 95%: 1.2-14.9), p: 0.025). Conclusions: Trapezoid tunnels placed medial to 24 mm or 15% medial to clavicle length could lead to higher probabilities of significant reduction loss. These findings support the importance of clavicular tunnels' proper placement for decreasing significant reduction loss.

Anatomic coracoclavicular ligament reconstruction with triple flip-buttons leads to good functional outcomes and low reduction loss: a case series.

BACKGROUND: The management of acromioclavicular (AC) joint dislocation remains controversial. Recently, anatomic coracoclavicular (CC) fixation with a double clavicular tunnel and three flip-buttons has shown promising results. This study aimed to evaluate functional and radiological outcomes in patients with high-grade AC joint dislocation treated with anatomic CC fixation using double clavicular tunnels and three flip-buttons. METHODS: A retrospective, unicentric study was performed. The study included patients with high-grade AC joint dislocation who underwent surgery with anatomic CC fixation using double clavicular tunnels and three flip-buttons. Demographic data were obtained from medical records. A functional evaluation using subjective shoulder value (SSV), visual analog scale (VAS), and disabilities of the arm, shoulder, and hand (DASH) questionnaires was performed, and an evaluation of preoperative and postoperative comparative Zanca view images was performed. Factors associated with functional outcomes and radiological AC reduction were analyzed. RESULTS: A total of 83 patients completed follow-up and were included in the analysis. The mean SSV, VAS, and DASH scores were 92.8, 0.8, and 6.4, respectively. Patients who had complications experienced significantly worse functional outcomes (DASH: P=0.037). Suboptimal final AC reduction was observed in nine patients (11.1%), and significantly more frequently in patients older than 40 years (P=0.031) and in surgeries performed more than 7 days after injury (P=0.034). There were two reoperations (2.4%). CONCLUSIONS: Anatomic CC fixation with a double clavicular tunnel and three flip-buttons leads to good functional outcomes, low complication rates, and high rates of optimal AC reduction. Level of Evidence: Level IV; Case series.

Determination of PASHs by various analytical techniques based on gas chromatography-mass spectrometry: application to a biodesulfurization process.

Polycyclic aromatic sulphur heterocyclic (PASH) compounds, such as dibenzothiophene (DBT) and alkylated derivatives are used as model compounds in biodesulfurization processes. The development of these processes is focused on the reduction of the concentration of sulphur in gasoline and gas-oil [D.J. Monticello, Curr. Opin. Biotechnol. 11 (2000) 540], in order to meet European Union and United States directives. The evaluation of biodesulfurization processes requires the development of adequate analytical techniques, allowing the identification of any transformation products generated. The identification of intermediates and final products permits the evaluation of the degradation process. In this work, seven sulfurated compounds and one non-sulfurated compound have been selected to develop an extraction method and to compare the sensitivity and identification capabilities of three different gas chromatography ionization modes. The selected compounds are: dibenzothiophene (DBT), 4-methyl-dibenzothiophene (4-m-DBT), 4,6-dimethyl-dibenzothiophene (4,6-dm-DBT) and 4,6 diethyl-dibenzothiophene (4,6 de-DBT), all of which can be used as model compounds in biodesulfurization processes; as well as dibenzothiophene sulfoxide (DBTO(2)), dibenzothiophene sulfone (DBTO) and 2-(2-hydroxybiphenyl)-benzenesulfinate (HBPS), which are intermediate products in biodesulfurization processes of DBT [ A. Alcon, V.E. Santos, A.B. Martín, P. Yustos, F. García-Ochoa, Biochem. Eng. J. 26 (2005) 168]. Furthermore, a non-sulfurated compound, 2-hydroxybiphenyl (2-HBP), has also been selected as it is the final product in the biodesulfurization process of DBT [A. Alcon, V.E. Santos, A.B. Martín, P. Yustos, F. García-Ochoa. Biochem. Eng. J. 26 (2005) 168]. Since, typically, biodesulfurization reactions take place in a biphasic medium, two extraction methods have been developed: a liquid-liquid extraction method for the watery phase and a solid phase extraction method for the organic phase. Recoveries of the selected compound in both media were studied. They were in the range of 80-100% for the watery and in the range of 40-60% for the organic phase, respectively. Gas chromatography coupled to mass spectrometry (GC-MS) has been employed for the identification of these selected compounds. Three different ionization modes were applied: conventional electron impact (EI); positive chemical ionization (PCI), using methane as the reagent gas; and a recently developed ionization mode known as hybrid chemical ionization (HCI), using perfluorotri-n-butylamine as the reagent gas. Limits of detection and identification capabilities have been compared between the three analytical techniques. The sensitivity of the three analytical techniques was studied and LOD between 0.05 and 1, between 0.09 and 2 and between 0.001 and 0.043 were achieved for PCI, EI and HCI, respectively. The developed method was applied in samples from a biodesulfurization process. The biodesulfurization reactions were conducted in resting cell operation mode, using Erlenmeyer flasks or an agitated tank bioreactor. The microorganism employed was Pseudomonas putida CECT 5279. The reaction was performed under controlled air flow, stirring and temperature conditions.