English to Italian Medical Medical (general) chirurgia

Si tratta di un manuale americano di chrirurgia, capitolo relativo al sistema biliare.
Nel paragrafo sulle lesioi alle vie biliari identificate dopo la colecistectomia, disgnosi e gestione, tecniche di intervento radiologico ed endoscopico, trovo queste frasi:

Endoscopic balloon dilation of bile duct strictures is generally reserved for those with primary bile duct strictures or patients who have undergone choledochoduodenostomy for reconstruction because the Roux limb does not usually allow endoscopic strategies. Therefore, series are limited, but results are encouraging, with 88% of patients responding to therapy and a complication rate of 8% from pancreatitis and cholangitis.

le serie sono limitate?? ha senso in medicina?
Grazie.