IPP implantation is a well-known, established, and considerably satisfactory treatment option for ED. Although an IPP is regarded to have good mechanical reliability in the long term, patient satisfaction with penile length after surgery has not been achieved because of the patient’s expectation in relation to the preimplantation erect penis length. The causes of dissatisfaction with the penile length are long ED duration, obesity, in which there are added tissues in the prepubic area, and acquired penile disorder such as Peyronie’s disease . Deveci et al.  reported the stretched flaccid penile length before and after two- or three-piece IPP implantation in 56 patients. Although there were no statistically significant differences between the preoperative and postoperative penile lengths, 72% of the patients complained of a decrease in penile length after surgery. However, one study comparing the erect penile length after IPP implantation, through induced intracavernosal injection of vasoactive agents, with the length before surgery found that all 11 patients experienced a decrease in erect penile length, from 0.2 to 3.0 cm, after IPP implantation. Furthermore, 45.5% of the recipients reported that their subjective penile length shortened after surgery, and no patient thought that his postoperative penile length was longer than its preoperative length . Henry et al.  prospectively assessed penile length measurements for 1 year after IPP implantation with the Coloplast Titan (Coloplast, Minneapolis, MN, USA), using an aggressive new length measurement technique to overcome reduced penile length. These patients underwent daily inflation of the IPP for 6 months and maximal inflation for 1–2 h daily for 6–12 months. Of these patients, 64.5% were satisfied with their penile length at 1 year and 74.2% of patients reported that their penile length increased. Because of the aggressive cylinder sizing and postoperative penile rehabilitation inflation protocol, all of the patients, except for two, experienced an increase (approximately 1 cm) in the stretched penile length. To prevent penile shortening, concomitant surgical interventions, such as a sliding technique, suprapubic lipectomy, suspensory ligament release, and ventral phalloplasty, have been developed and used [11, 12].
Although the exact mechanism of penile length shortening after IPP implantation has not been fully elucidated, incorrectly measuring the corporeal length during surgery and lack of glans tumescence after implantation might decrease the penile length . Intraurethral alprostadil injection or oral phosphodiesterase type 5 inhibitors are used for enhancing the soft glans after penile prosthesis implantation to increase the length of a shortened penis [13, 14].
In the 1990s, the AMS 700 Ultrex penile prosthesis was developed to prevent penile shortening and increase penile girth and length. Montague et al.  reported that 50 patients underwent implantation using the AMS 700 Ultrex. The penile length was increased by 1 cm in 12 patients, and in 28 patients, the postoperative penile length was the same as the intraoperative length expansion. However, because S-shaped deformities have occurred when using the AMS 700 Ultrex prosthesis and its durability is low, urologists have been discouraged from using this IPP. AMS 700 LGX, which allows both girth and length expansion of the cylinders with up to 20% elongation, was developed to overcome these disadvantages. Recently, one prospective study reported the mean penile length and recipient satisfaction after AMS 700 LGX implantation . At 6 and 12 months, the stretched flaccid penile length was longer than the preoperative length. Six and 12 months postoperatively, the IIEF desired domain scores and overall satisfaction scores were statistically different from the preoperative scores. However, the mean Erectile Dysfunction Inventory of Treatment Satisfaction scores did not show significant improvement after implantation.
In the present study, at 6 and 12 months postoperatively, the stretched penile length was longer than the preoperative length. We confirmed that all postoperative total IIEF scores, postoperative IIEF erectile function domain scores, and postoperative satisfaction domain scores significantly improved, compared with the preoperative scores. Furthermore, complications such as infection, skin necrosis, and erosion occurred rarely. The mechanical malfunction rate was also very low, and no mechanical complications such as a cylinder aneurysm or S-shaped deformity occurred. Therefore, the AMS 700 LGX is an excellent IPP to preserve penile length in patients who are concerned about decreases in their original penile length and has a low rate of complications and mechanical malfunction.
The present study has several limitations. First, this is a retrospective study. Second, the IPP implantation procedures were performed by an andrologist who performs a high volume of these procedures; therefore, it is difficult to generalize our results to surgeons who are less experienced. Third, this study excluded patients with Peyronie’s disease and corporal fibrosis as well as those who underwent a reoperation. A further study about the usefulness of AMS 700 LGX in patients with these conditions should be performed. Fourth, there are no validated questionnaires for evaluating erection and patient satisfaction with the IPP; hence, we used the IIEF to evaluate patients’ satisfaction. Thus, an IPP-specific validated questionnaire should be developed in the future. Finally, we did not record the patients’ weight, which could have resulted in some differences in the stretched flaccid penile lengths. Despite these limitations, our present study provides data on the outcomes of the use of and patient satisfaction with the AMS 700 LGX penile prosthesis in Korea for the first time.