CHANGES IN LUNG LOBAR VOLUME AND BRONCHIAL DEFORMITY AFTER RIGHT UPPER LOBECTOMY

To explore the anatomical repositioning of the middle lobe following r ight upper (RU) lobectomy, we measured the lobar volumes of the lung a nd the branching angles of the airway, and defined their changes after RU lobectomy in a rabbit model, Groups Al (It = 10) and A2 (n = 10) w ere control groups and groups BI (rt = 10) and B2 (n = 10) underwent R U lobectomy, Casting material was introduced into the airway and a hea rt-lung bloc was removed form the thoracic cavity in all groups, In gr oups Al and B1, the volume of each lobe of the bilateral lungs was mea sured, while in groups A2 and B2, bronchial casts were made and the br anching angles of the airway were measured. The volume ratio of the ri ght upper lobe (RUL) to the total lung was 12.0 +/- 0.4% in group Al; however, after RU lobectomy, the volume ratio of the right middle lobe (RML) to the total lung increased from 8.7 +/- 0.6% in group Al to 13 .5 +/- 0.8% in group B1. The volume of the left lung also increased fr om 43.0 +/- 0.5% in group Al to 48.8 +/- 1.1% in group B1. The angle b etween the truncus intermedius and the RML bronchus was significantly smaller in group B2, at 109.0 +/- 3.5 degrees, than in group A2, in wh ich it was 138.5 +/- 1.7 degrees. The angle between the RML bronchus a nd the coronal plane was 57.5 +/- 2.5 degrees in group A2 and 33.5 +/- 3.3 degrees in group B2. Our method of measuring the bronchial branch ing angle subsequent to RU lobectomy proved useful to illustrate posto perative positional changes and expansion of the remaining lobes.