Sexual dysfunction is a long-term complication of rectal cancer treatment, affecting both men and women. Sexual dysfunction is described as symptoms that may include impotency, the inability to ejaculate, erectile dysfunction, decreased sexual desire or dyspareunia and poor vaginal lubrication.[1] Autonomic nerve injuries during rectal resection are major contributing factors that may cause urinary and sexual dysfunction. Erectile dysfunction may be the most common autonomic nerve-related complication after rectal resection in men while dyspareunia and poor lubrication are most common in women.[2]

Both sympathetic and parasympathetic nerve injury may occur during TME [Figure 1-2]. There are 4 operative sites that are at particular risk for nerve injury.[3]

Figure 1. Autonomic Nerves

Figure 2

1. Origin of the inferior mesenteric artery (IMA). Injury to the superior hypogastric sympathetic nerve plexus above the sacral promontory and near the IMA origin causes ejaculatory dysfunction, often manifest as retrograde ejaculation. This can be avoided by preserving the sympathetic superior hypogastric plexus nerve fibers near the origin of the IMA and more distal hypogastric nerve trunks, and by minimizing traction on the IMA origin while leaving a 1-cm pedicle at the root of the IMA during division.

2. Posterior rectal TME dissection. TME starts at the sacral promontory where the left and right hypogastric nerves may be visualized coursing down the sacral concavity toward the deep pelvis. These nerves are sympathetic. Identification of these nerves while dissecting in the correct plane between the fascia propria of the rectum and presacral fascia allows nerve preservation.[4]

3. Lateral rectal TME dissection. Excessive traction or wide lateral dissection along the lateral stalks may cause injury to the inferior hypogastric plexus that contains sympathetic fibers from the hypogastric nerves and parasympathetic fibers from the sacral nerves (S2-S3-S4). Thermal injury to neurons may occur with extensive electrocautery. It is important to stay in the mesorectal plane leaving nerve fibers lateral to the mesorectum.

4. Anterior rectal TME dissection. The integrity of Denonvillier’s fascia, invested by the periprostatic plexus, should be preserved during anterior TME dissection between the fascia propria of the rectum and the prostate and seminal vesicles, except when it is necessary for an R0 resection of an anterior tumor. Injury to the parasympathetic nerve supply in the nervi erigentes at this location may be the most common autonomic TME injury and may result in erectile dysfunction and dyspareunia. Prior to the advent of TME, postoperative erectile dysfunction and retrograde ejaculation rates were observed in 25% to 75% of cases. However, careful adherence to TME mesorectal dissection planes has decreased this rate to 10% to 29% of cases.[5]

Adhering to mesorectal dissection planes and identifying superior hypogastric plexus nerve fibers, left and right hypogastric nerves in the sacral concavity, and inferior hypogastric plexus nerves during lateral and anterior dissection are key to avoiding sexual dysfunction after TME. Studies evaluating the impact of neoadjuvant radiotherapy on sexual dysfunction are not conclusive and it is uncommon for radiotherapy to be considered the only causative factor. More data may become available in future studies of sexual dysfunction in patients who have a complete clinical response after neoadjuvant therapy and who undergo nonoperative surveillance rather than TME.[3] Other risks factors for sexual dysfunction are thought to include abdominoperineal resection (APR), age over 65 years, and pelvic sepsis from postoperative anastomotic leak or abscess.[6]

Management of postoperative sexual function is multifactorial. Pilot studies of patients with neurogenic impotence after prostatectomy have shown that multi-disciplinary treatment, including sexual counseling and behavioral therapy, can demonstrate improvement within 6-12 months.[7] Following proctectomy, pharmacologic treatment with phosphodiesterase inhibitors, such as oral sildenafil, has been shown to improve sexual function in 80% of patients compared to 17% with placebo.[2] Other options include local intracavernous and intraurethral injections and vacuum-constriction devices.[8] Counseling not only helps to reassure patients and their partners but may also enhance response to medical therapy.[9] Ultimately, in the event of failure of behavioral and pharmacologic therapies, placement of a penile prosthesis is effective but irrevocable and may be considered as a last resort.

The possibility of sexual dysfunction as a complication of rectal cancer treatment should be part of the pretreatment conversation with the patient. Greater than 50% of patients feel they do not receive satisfactory preoperative education relevant to sexual dysfunction. Only 9% of women are told of the possibility of sexual dysfunction after TME and < 10% of men and women receive specialty consultation when sexual dysfunction occurs after TME.[3]