Surgery of the Scrotum

Scrotal Wall
 

A detailed understanding of the scrotal anatomy is critical in the operative planning of scrotal and pelvic surgeries. Knowledge of scrotal wall anatomy enables safer access into the scrotum for common scrotal procedures, facilitates identification of surgical planes during surgical debridement, and allows for multilayer closures.
 

The scrotal skin is rugated because of its underlying attachment to the dartos muscle, deeply pigmented, and hair-bearing. In contrast with other parts of the body, the scrotum is elastic and highly-temperature regulated to enable spermatogenesis.

Scrotal Contents
 

Scrotal contents are maintained in their position within the scrotal cavity by the spermatic cord and gubernacular attachments. The testicle is intimately encased by the tunica albuginea, and protected by the layers of tunica vaginalis, internal and external spermatic fascia (separated by a layer of cremasteric muscle), and ultimately covered by the dartos layer and scrotal skin. The dartos fascial layer acts as a barrier to the spread of necrotizing fasciitis to deeper structures in the scrotum (Figs. 83.1 and 83.2). 

The epididymis originates from the efferent ducts of the rete testis in mediastinum testis. It is located along the posterolateral aspect of the testis, with its head (caput) located superiorly, the body (corpus)
along the longitudinal axis of the testis, and the tail (cauda) at the inferior testicular pole. The vas deferens begins as continuation of the cauda epididymis, travels along the spermatic cord into the pelvis, where it becomes ampulla of the vas, joins with seminal vesicles (SVs), and forms the proximal ejaculatory duct. Two nonfunctional, vestigial structures may be encountered in the scrotum: the appendix testis over the upper pole of the testis and the appendix epididymis attached to the head of the epididymis.

Vasculature
 

The scrotum is highly vascularized, with blood supply provided anteriorly from the superficial external pudendal artery and deep external pudendal artery, and posteriorly from the posterior scrotal artery. Venous drainage follows the arterial supply draining into the external pudendal vein and posterior scrotal vein, which empty into the great saphenous vein and to the internal iliac veins, respectively.
 

In addition to temperature regulation, the thin, highly vascular nature of the scrotal skin allows increased transdermal medication absorption, up to 40 times the absorption of other parts of the body (Nieschlag and Behre, 2010). This absorptive quality of the scrotal skin was utilized in testosterone supplementation; however, the necessity of frequent scrotal hair clipping made continued application of scrotal testosterone patches cumbersome for patients, and this formulation of testosterone is no longer available. Additionally, the scrotal skin is high in 5α-reductase enzyme, and as result, high dihydrotestosterone levels were seen with scrotal transdermal testosterone therapy (Ahmed et al., 1988).
The blood supply to the testis arises from the aorta as the testicular artery, from the internal iliac artery as the artery to the ductus deferens, and from the external iliac artery as the cremasteric artery. The epididymis is nurtured by the superior epididymal artery from the testicular artery and from the inferior epididymal artery, arising as branches off the deferential artery and distal branches of the testicular artery. Although the majority of the blood supply (~84%) to the epididymis comes from the superior epididymal artery, the superior epididymal artery can be sacrificed to gain additional testicular mobilization during vasectomy reversal because of the vascular anastomoses between the superior and inferior epididymal artery (Strittmatter and Konrad, 1989). Understanding the blood supply to the epididymides is important in the surgical treatment of epididymal disease. Important anastomoses are also present cranial and caudal to the testis. Cranially, thin-caliber anastomoses are often present in the spermatic cord between the testicular artery and the deferential artery approximately 10 cm above the testis (Strittmatter and Konrad, 1989). At the level of the cauda of the
epididymis, anastomoses form between the testicular artery, deferential artery, and cremasteric artery. This redundancy of blood supply to the testis allows viability of the testis if one or two of the arteries are injured or ligated.

Innervation
The scrotum is innervated by autonomic and somatic nerve fibers. Three groups of converging autonomic nerve fibers contribute to the autonomic innervation of the testes: (1) superior spermatic nerves, from the renal and mesenteric plexi, which follow the testicular artery, (2) middle spermatic nerves, from the superior hypogastric plexus, which travel adjacent to the vas as it enters the internal spermatic ring, and (3) inferior spermatic nerves, which originate from the inferior hypogastric plexus (Patel, 2017). The inferior spermatic nerve fibers fuse with the middle spermatic nerve fibers at the prostate-vesical junction, run within the spermatic cord along the vas deferens, and ultimately penetrate the epididymis and testis (Sosa et al., 2009; Patel, 2017). In addition to the sensory fibers contained in the autonomic spermatic nerves, afferent fibers of these nerves are also important in the endocrine control of the testis. Sosa et al. demonstrated the endocrine control over testis function by modulating androgen release in adult male rats via exposure of autonomic ganglia to adrenoreceptor agonists and antagonists (Sosa et al., 2009). Exposure of the inferior mesenteric plexus ganglia to noradrenaline resulted in significantly higher serum testosterone levels compared with untreated ganglia in the control male rats; however, noradrenaline exposure to the superior mesenteric ganglia did not influence testosterone concentrations. The scrotum is also innervated by somatic nerves, including ilioinguinal and genitofemoral nerves. The genital branch of the genital femoral nerve is positioned on the inferolateral aspect of the spermatic cord and innervates the anterolateral scrotal skin, the tunica vaginalis, and the cremaster muscles (Ducic and Dellon, 2004; Zorn et al., 1994). In contrast, the ilioinguinal nerve sits on the anterior of the cremasteric muscles and innervates the anterior scrotal skin (Wijsmuller et al., 2007). An understanding of the course of these nerves is important in scrotal denervation procedures, which are discussed later in this chapter.

10 a) Describe the surgically correctible causes leading to recurrent UTI (Urinary Tract Infection). b) What are the recent trends in management of recurrent UTI?

https://sites.google.com/site/surgerypaper/2019/uti

UTI is an inflammatory response of the urothelium to bacterial invasion that is usually associated with bacteriuria and pyuria.

Bacteriuria is the presence of bacteria in the urine. 

Pyuria, the presence of white blood cells (WBCs) in the urine, is generally indicative of infection and/or an inflammatory response of the urothelium to bacteria, stones, an indwelling foreign body, or other conditions that can contribute to pyuria. 

Bacteriuria without pyuria is generally indicative of bacterial colonization without overt infection of the urinary tract. Pyuria without bacteriuria, or sterile pyuria, warrants further evaluation (see the discussion of pyuria in the section on urinalysis).

Cystitis describes a clinical syndrome of dysuria, frequency, urgency, and occasionally suprapubic pain. 

Acute pyelonephritis is a clinical syndrome of chills, fever, and flank pain that is accompanied by bacteriuria and pyuria, a combination that is reasonably specific for an acute bacterial infection of the kidney.

Chronic pyelonephritis describes a shrunken, fibrosed kidney, diagnosed by morphologic, radiologic, or functional evidence of renal disease that may be postinfectious but is frequently not associated with current (active) UTI.

UTIs may also be described in terms of the anatomic or functional status of the urinary tract and the health of the host. Uncomplicated describes an infection in a healthy patient with a structurally and functionally normal urinary tract; this often specifically refers to the absence of obstruction to any part of the urinary tract.

A complicated infection is associated with factors that increase the chance of acquiring bacteria and decrease the efficacy of therapy. The urinary tract is structurally or functionally abnormal, the host is compromised, and/or the bacteria have increased virulence or antimicrobial resistance.

Factors That Suggest a Complicated Urinary Tract
Infection
Functional or anatomic abnormality of urinary tract
Male gender
Pregnancy
Elderly patient
Diabetes
Immunosuppression
Childhood urinary tract infection
Recent antimicrobial agent use
Indwelling urinary catheter
Urinary tract instrumentation
Hospital-acquired infection
Symptoms for more than 7 days at presentation

UTIs may also be defined by their relationship to other UTIs: • A first or isolated infection is one that occurs in an individual who has never had a UTI or has one remote infection from a previous UTI. • An unresolved infection is one that has not responded to antimicrobial therapy and is documented to be the same organism with a similar resistance profile. • A recurrent infection is one that occurs after documented, successful resolution of an antecedent infection. Consider these two different types of recurrent infection: 1. Reinfection describes a new event associated with reintroduction of bacteria into the urinary tract. 2. Bacterial persistence refers to a recurrent UTI caused by the same bacteria reemerging from a focus within the urinary tract, such as an infectious stone or the prostate. Relapse is frequently used interchangeably. These definitions require careful clinical and bacteriologic assessment and are important because they influence the type and extent of the patient's evaluation and treatment.

 

The sequelae of complicated UTIs are substantial. It is well established in the presence of obstruction, infection stones, diabetes mellitus, and other risk factors that UTIs in adults can lead to progressive renal damage. The long-term effects of uncomplicated recurrent UTIs are not completely known, but, so far, no association between recurrent infections and renal scarring, hypertension, or progressive renal azotemia has been established.

• UTIs are the most common bacterial infection and, as such, make a significant impact on health care costs.
• The incidence of bacteriuria increases with institutionalization/hospitalization as well as with pregnancy and certain comorbidities that alter lower urinary tract function or cause immunosuppression.
• No clear association has been described between recurrent uncomplicated UTIs and renal sequelae such as scarring, hypertension, or progressive renal insufficiency.

Pathogenesis:

UTIs occur as a result of interactions between the uropathogen and the host. Successful infection of the urinary tract is determined in part by the virulence factors of the bacteria, the inoculum size, and the inadequacy of host defense mechanisms. 

Routes of Infection

Ascending Route

Most bacteria enter the urinary tract from the bowel and skin reservoir via ascent through the urethra into the bladder. Adherence of pathogens to the introital and urothelial mucosa plays a significant role in ascending infections.

Most episodes of pyelonephritis are caused by retrograde ascent of bacteria from the bladder through the ureter to the renal pelvis and parenchyma. Although reflux of urine is probably not required for ascending infections, edema associated with cystitis may cause sufficient changes in the ureterovesical junction to permit reflux. Once the bacteria are introduced into the ureter, they may ascend to the kidney unaided. However, this ascent would be greatly increased by any process that interferes with the normal ureteral peristaltic function. Gram-negative bacteria and their endotoxins, as well as pregnancy, ureteral obstruction, and high lower tract pressures have a significant antiperistaltic effect.

Bacteria that reach the renal pelvis can enter the renal parenchyma by means of the collecting ducts at the papillary tips and then ascend upward within the collecting tubules.

Hematogenous Route
Infection of the kidney by the hematogenous route is uncommon in normal individuals. However, the kidney is occasionally secondarily infected in patients with Staphylococcus aureus bacteremia originating from oral sites or with Candida fungemia. Experimental data indicate that infection is enhanced when the kidney is obstructed.
 
Lymphatic Route
Direct extension of bacteria from the adjacent organs via lymphatics may occur in unusual circumstances, such as a severe bowel infection or retroperitoneal abscesses. There is little evidence that lymphatic routes play a significant role in the majority of UTIs.