Outside-in technique

Outside-in technique It can verify if there is a leak and quantify the size of a leak. The tracer gas must be on the outside of the piece in question. It can provide a fast go/no-go operation. It cannot tell you where the leak is. 

Some of the other leak detection methods explained earlier in this section are based on these techniques. Methods such as bagging parts of a vacuum system and filling the bagged parts with a probe gas are similar to the outside-in technique. However, it is not possible to quantify a leak with this approach. Alternatively, filling a container with gas and either submerging it in a liquid or covering it with a bubbling solution is similar to the detector-probe technique. 

Fig. 7.61 With the outside-in technique, the piece in question is directly connected to the helium leak detector. A covering, or hood, is placed all around the tested piece and is filled with helium. Any helium escaping into the tested piece will be detected by the helium leak detector. From Introduction to Helium Mass Spectrometer Leak Detection, Figs. 3.3 and 3.4, by Varian Associates, Inc. 1980, reproduced with permission.

Our surgical technique to ACL deficiency is what is called anatomic ACL reconstruction for most of the cases. The exception is the patients with wide open epiphysis and multiple-ligament reconstruction cases. For the patients with wide open epiphysis, we try to avoid the epiphyseal plate injury by approaching from outside-in technique for the femoral side that makes double-bundle reconstruction difficult (Fig. 24.1). For the cases with multiple-ligament reconstruction, we try to... 

Ahn JH, Lee YS, Lee SH (2014) Creation of an anatomic femoral tunnel with minimal damage to the remnant bundle in remnant-preserving anterior cruciate ligament reconstruction using an outside-in technique. Arthrose Tech 3 e 175-el79... 

The creation of an anatomically correct femoral tunnel is possible through any femoral tuimel creation method, such as transtibial, transportal, and outside-in techniques. 

However, to practice the behind-remnant approach more easily, the outside-in technique will be the best because adequate room for arthroscopic procedures and observation can be achieved [16]. 

Based on the preoperative radiographs and 3D CT, whether the previous bone tunnel should be overdrilled or not had been determined for each AM and PL tunnel. When the previous tuimel will be overdrilled, the new femoral tunnel should be created by the other femoral tuimel creation technique. That is, if the previous femoral tunnels were created by transtibial technique, the new tunnels had better be created by portal or outside-in technique. Changed femoral tunnel creation technique will make the femoral tunnel direction change with refreshed bone tunnel walls. When the position of the previous femoral tunnels was determined to change, the new guide pin can be put on the edge of the previous tuimels or outer. 

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