Should I do penile injections after surgery to help restore erections?

Injections that produce an erection, tension devices that stretch the flaccid penis, vacuum erection devices...all increase blood flow to the chambers in the penis that swell during erection. So do the pills (based on a chemical process involving nitrous oxide.)
So regardless of which or how many of these treatments are used, the "exercise" of these muscles (it's called smooth muscle tissue) is believed to maintain their health with the result that natural erections may occur once the trauma to the nerves of surgery has passed (or perhaps even some nerves have learned alternative paths, as they apparently also sometimes do.)
Generally the belief is that we will only regain some or all of our (still declining with age and time) erectile function. However, vacuum erection devices are advertised to others (not men living with cancer) as increasing erectile function. But is this actual medical science or just marketing hype?
The figure you may hear cited is that men typically have about four (usually nocturnal) erections daily and that when that is not happening due to the surgical trauma and nerve damage, stimulating it to happen aids in recovery.
In any case, that's the theory as best I understand and can explain 🙂

Thanks, good explanation. I'm doing some electro-accupuncture. I read it might be useful in helping restore erections. We'll see! Had prostatectomy six weeks ago.

I'll tell you what worked for me. I had a nerve-sparing radical prostatectomy 11 months ago at age 74. Prior to that I had "penis in vagina" intercourse to orgasm twice a month on average, and that was my goal to return to, which I have done over the past two months. For the past two months I have scored 22-23 out of 25on the IIEF 5 question scale, which is considered normal erectile/sexual function.

So how did I get there. It started with a healthy and supportive wife, and my determination to apply analysis, persistence, and discipline to my penile rehab. The surgeon prescribed daily viagra for 6 months. I found a program from Australia by a physical therapist Melissa Hadley Barrett https://melissahadleybarrett.com/penile-rehabilitation-program/

I bought a Vacuret vacuum device and used it 5-6 times a week. In addition, I self stimulated to orgasm with an Octopussy vibrator, designed for use with a flaccid penis, 2-3 times a week. After I felt physically recovered from the surgery - 4 months out - and emotionally ready, my wife and I began experimenting with what and what didn't work.

At my six-month post-op visit, I told the surgeon I would consider penile injection if I was not seeing some success by the nine month mark. That's when we started putting all together. I am still using the pump, and use 100mg sildenifil (generic Viagra) before attempting sex, and I feel I have met my goal of returning to my previous capabilities.

I'm not saying this is a medically proven program; it is what worked for me.