Anatomy and Pathophysiology
Hemorrhoids are clusters of vascular tissues, smooth muscles, and connective tissues
that lie along the anal canal in three columns—left lateral, right anterior, and right
posterior positions. Because some do not contain muscular walls, these clusters may
be considered sinusoids instead of arteries or veins ([Fig. 1]).[3] Hemorrhoids are present universally in healthy individuals as cushions surrounding
the anastomoses between the superior rectal artery and the superior, middle, and inferior
rectal veins. Nonetheless, the term “hemorrhoid” is commonly invoked to characterize
the pathologic process of symptomatic hemorrhoid disease instead of the normal anatomic
structure.
Fig. 1 Anatomy of the anal canal and vasculature of hemorrhoids. (Reprinted with permission
from Cintron J, Abcarian H. Benign anorectal: hemorrhoids. In: The ASCRS Textbook
of Colon and Rectal Surgery. New York, NY: Springer-Verlag, Inc; 2007:156–77; with
kind reprint permission of Springer Science + Business Media.)
Classification of a hemorrhoid corresponds to its position relative to the dentate
line. External hemorrhoids are located below the dentate line and develop from ectoderm
embryonically. They are covered with anoderm, composed of squamous epithelium, and
are innervated by somatic nerves supplying the perianal skin and thus producing pain.
Vascular outflows of external hemorrhoids are via the inferior rectal veins into the
pudendal vessels and then into the internal iliac veins. In contrast, internal hemorrhoids
lie above the dentate line and are derived from endoderm. They are covered by columnar
epithelium, innervated by visceral nerve fibers and thus cannot cause pain. Vascular
outflows of internal hemorrhoids include the middle and superior rectal veins, which
subsequently drain into the internal iliac vessels.
While no taxonomy of external hemorrhoids is used clinically, internal hemorrhoids
are further stratified by the severity of prolapse. First-degree internal hemorrhoids
do not prolapse out of the canal but are characterized by prominent vascularity. Second-degree
hemorrhoids prolapse outside of the canal during bowel movements or straining, but
reduce spontaneously. Third-degree hemorrhoids prolapse out of the canal and require
manual reduction. Fourth-degree hemorrhoids are irreducible even with manipulation.[4]
The exact pathophysiology of symptomatic hemorrhoid disease is poorly understood.
Previous theories of hemorrhoids as anorectal varices are now obsolete—as shown by
Goenka et al, patients with portal hypertension and varices do not have an increased
incidence of hemorrhoids.[5] Currently, the theory of sliding anal canal lining, which proposes that hemorrhoids
occur when the supporting tissues of the anal cushions deteriorate, is more widely
accepted. Advancing age and activities such as strenuous lifting, straining with defecation,
and prolonged sitting are thought to contribute to this process. Hemorrhoids are therefore
the pathological term to describe the abnormal downward displacement of the anal cushions
causing venous dilatation.[6] On histopathological examination, changes seen in the anal cushions include abnormal
venous dilatation, vascular thrombosis, degenerative process in the collagen fibers
and fibroelastic tissues, and distortion and rupture of the anal subepithelial muscle.
In severe cases, a prominent inflammatory reaction involving the vascular wall and
surrounding connective tissue has been associated with mucosal ulceration, ischemia,
and thrombosis.[7]
Symptoms and Presentation
A total of 40% of individuals with hemorrhoids are asymptomatic.[8] For symptomatic hemorrhoids, there is great variance in the constellation of symptoms.
In addition, many other anorectal pathologies such as anal fissure, fistula, pruritus,
condyloma, and even anal cancer are often labeled as “hemorrhoids” by the layperson.
For internal hemorrhoids, bleeding is the most commonly reported symptom. The occurrence
of bleeding is usually associated with defecation and almost always painless. The
blood is bright red and coats the stool at the end of defection. Blood can be found
on the toilet paper, dripping into the bowl, or even dramatically spraying across
the toilet bowl. Another frequent symptom is the sensation of tissue prolapse. Prolapsed
internal hemorrhoids may accompany mild fecal incontinence, mucus discharge, sensation
of perianal fullness, and irritation of perianal skin. Pain is significantly less
common with internal hemorrhoids than with external hemorrhoids, but can occur in
the setting of prolapsed, strangulated internal hemorrhoids that develop gangrenous
changes due to the associated ischemia.
In contrast, external hemorrhoids are more likely to be associated with pain, due
to activation of perianal innervations associated with thrombosis. Patients typically
describe a painful perianal mass that is tender to palpation. This painful mass may
be initially increasing in size and severity over time. Bleeding can also occur if
ulceration develops from necrosis of the thrombosed hemorrhoid, and this blood tends
to be darker and more clotted than the bleeding from internal disease. Painless external
skin tags often result from previous edematous or thrombosed external hemorrhoids.
Management of Hemorrhoid Disease
The natural history of most cases of hemorrhoid disease is self-limited. For symptomatic
hemorrhoid disease that presents to the clinic or emergency room, treatments range
from nonoperative medical interventions and office-based procedures to surgery. One
general guiding principle is that the least-invasive approaches should be considered
first, except in cases of acute thrombosis. Specific choices of treatments depend
on patients' age, severity of symptoms, and comorbidities. A summary of management
strategies is shown in [Table 1].
Table 1
Summary of management options for hemorrhoids
|
Treatment
|
Grade I
|
Grade II
|
Grade III
|
Grade IV
|
Acute thrombosis and strangulation
|
|
Dietary and lifestyle modification
|
X
|
X
|
X
|
X
|
X (after acute event)
|
|
Office procedures
|
|
|
|
|
|
|
Rubber band ligation
|
X
|
X
|
X
|
|
|
|
Sclerotherapy
|
X
|
X
|
|
|
|
|
Infrared coagulation
|
X
|
X
|
|
|
|
|
Operating-room procedures
|
|
|
|
|
|
|
Hemorrhoidectomy
|
|
|
X
|
X
|
X (emergent)
|
|
Stapled hemorrhoidopexy
|
|
|
X
|
X
|
|
|
Doppler-guided hemorrhoid artery ligation
|
|
X
|
X
|
|
|
Source: Adapted and modified with permission from Cintron J, Abcarian H. Benign anorectal:
hemorrhoids. In: The ASCRS Textbook of Colon and Rectal Surgery. New York, NY: Springer-Verlag,
Inc; 2007:156–77; with kind reprint permission of Springer Science + Business Media.
Conservative Medical Treatments
Lifestyle and dietary modification are the mainstays of conservative medical treatment
of hemorrhoid disease. Specifically, lifestyle modifications should include increasing
oral fluid intake, reducing fat consumptions, avoiding straining, and regular exercise.
Diet recommendations should include increasing fiber intake, which decreases the shearing
action of passing hard stool. In a meta-analysis of seven randomized trials comparing
fiber to nonfiber controls, fiber supplementation (7–20 g/d) reduced risk of persisting
symptoms and bleeding by 50%. However, fiber intake did not improve symptoms of prolapse,
pain, and itching.[9]
For symptomatic control, topical treatments containing various local anesthetics,
corticosteroids, or anti-inflammatory drugs are available. Notable topical drugs include
0.2% glyceryl trinitrate, which has been studied to relieve grade I or II hemorrhoids
with high resting anal canal pressures, but is associated with headaches in 43% of
patients.[10] Patients also commonly self-medicate with Preparation-H (Pfizer Incorporated, Kings
Mountain, NC), a formulation of phenylephrine, petroleum, mineral oil, and shark liver
oil (vasoconstrictor and protectants), which provides temporary relief in acute symptoms
of hemorrhoids such as bleeding and pain on defecation.[11] Topic corticosteroids in cream or ointment formulations are commonly prescribed,
but their efficacy remains unproven.
Except in the case of thrombosis, both internal and external hemorrhoids respond readily
to conservative medical therapy. However, when medical interventions fail to resolve
symptoms or if the extent of hemorrhoid disease is severe, there are various options
for invasive procedures available to the colorectal surgeon.
Nonsurgical Office-based Procedures
For internal hemorrhoids, rubber band ligation, sclerotherapy, and infrared coagulation
are the most common procedures but there is no consensus on optimal treatment. Overall,
the goals of each procedure are to decrease vascularity, reduce redundant tissue,
and increase hemorrhoidal rectal wall fixation to minimize prolapse.
Rubber Band Ligation
Rubber band ligation is the most commonly performed procedure in the office and is
indicated for grade II and III internal hemorrhoids.[12] Contraindications include symptomatic external disease and patients with coagulopathies
or on chronic anticoagulation (due to risk of delayed hemorrhage). There is also an
increased risk of sepsis in immunocompromised patients.[13] Performing rubber band ligation does not require any local anesthetic. Patients
are placed in jackknife or left lateral position and the procedure is performed through
an anoscope. Several platforms are available, but the two most prevalent ligating
devices are the McGivney forceps ligator and the suction ligator. Small rubber band
rings are deployed tightly around the base of the internal hemorrhoids. They should
be placed at least half a centimeter above dentate line to avoid placement into somatically
innervated tissue ([Fig. 2]). Patients should be asked about presence of pain prior to release of rubber bands.
While it is safe to ligate more than one column during a single visit, some experts
recommend starting with a single column during the first visit to accurately assess
the patient's tolerance of the technique.[11]
Fig. 2 Banding of an internal hemorrhoid through an anoscope using a McGown suction-ligator.
(Adapted with permission from Cintron J, Abcarian H. Benign anorectal: hemorrhoids.
In: The ASCRS Textbook of Colon and Rectal Surgery. New York, NY: Springer-Verlag,
Inc; 2007:156–77; with kind reprint permission of Springer Science + Business Media.)
Rubber band ligation works by causing hemorrhoid tissue necrosis and its fixation
to the rectal mucosa. As the tissues become ischemic, necrosis develops in the following
3 to 5 days, and an ulcerated tissue bed is formed. Complete healing occurs several
weeks later. Complications are very uncommon, but those may occur include pain, urinary
retention, delayed bleeding, and very rarely perineal sepsis.
In a large review of 805 patients from a single practice that performed 2,114 rubber
band ligations, hemorrhoid disease requiring the placement of four or more bands was
associated with a trend in higher failure rates and greater need for subsequent hemorrhoidectomy.
Complications observed in this patient cohort included bleeding (2.8%), thrombosed
external hemorrhoids (1.5%), and bacteremia (0.09%). Higher bleeding rates were encountered
with the use of aspirin, nonsteroidal anti-inflammatory drugs, and warfarin.[14] Time to recurrence was less with subsequent treatment courses and treatment of recurrent
symptoms with rubber band ligation resulted in success rates of 73, 61, and 65% for
the first, second, and third recurrences, respectively. Cumulatively, a success rate
of 80% is observed with rubber band ligation.[12] Overall, banding is a safe, quick, and effective procedure for internal hemorrhoids.
Sclerotherapy
Sclerotherapy is indicated for patients with grade I and II internal hemorrhoids and
may be a good option for patients on anticoagulants. Like rubber band ligation, sclerotherapy
does not require local anesthesia. Performed through an anoscope, internal hemorrhoids
are located and injected with a sclerosant material—typically a solution including
phenol in vegetable oil—into the submucosa. The sclerosant subsequently causes fibrosis,
fixation to the anal canal, and eventual obliteration of the redundant hemorrhoidal
tissue. Complications of sclerotherapy include minor discomfort or bleeding. However,
rectal fistulas or perforation can very rarely occur due to misplaced injections.[15]
Infrared Coagulation
Infrared coagulation refers to direct application of infrared light waves to the hemorrhoidal
tissues and can be used for grade I and II internal hemorrhoids. To perform this procedure,
the tip of the infrared coagulation applicator is usually applied to the base of the
internal hemorrhoid for 2 seconds, with three to five treatments per hemorrhoid. By
converting infrared light waves to heat, the applicator causes necrosis of the hemorrhoid,
visualized as a white, blanched mucosa. Over time, the affected mucosa scars, leading
to retraction of the prolapsed hemorrhoid mucosa. This procedure is very safe with
only minor pain and bleeding reported.
As a comparison of the various office-based procedures, MacRae and McLeod conducted
a meta-analysis of 18 trials and concluded that rubber band ligation was better than
sclerotherapy in response to treatment for grade I and III hemorrhoids, with no differences
in the complication rate.[16] The authors also noted that patients treated with sclerotherapy or infrared coagulation
were more likely to require additional subsequent procedure or therapies in comparison
to those treated with rubber band ligation. Finally, although pain was greater after
rubber band ligation, recurrent symptoms were less common.
Surgical Procedures
Continued symptoms despite conservative or minimally invasive measures usually require
surgical intervention. In addition, surgery is the initial treatment of choice in
patients with symptomatic grade IV hemorrhoids or those who have strangulated internal
hemorrhoids. It may also be required for symptomatic grade III hemorrhoids and in
patients who present with thrombosed hemorrhoids.
For patients who present with thrombosed external hemorrhoids, surgical evaluation
and intervention within 72 hours of thrombosis may result in significant relief, as
pain and edema peak at 48 hours.[17] However, after 48 to 72 hours, organization of the thrombus and amelioration of
symptoms generally obviates the need for surgical evacuation, which is consistent
with the natural history of hemorrhoidal thrombosis. After the initial 72-hour window,
the pain typically plateaus and slowly improves, at which point the pain from hemorrhoid
excision would exceed the pain from the thrombosis itself.
For those patients requiring intervention, excision of the thrombosed hemorrhoid can
be performed in the office or emergency-room setting and rarely requires the operating
room. The thrombosed hemorrhoid should be injected with a local anesthetic, followed
by an elliptical incision and excision of the entire thrombosed hemorrhoid. Simple
incision and drainage is insufficient, and leads to increased rates of symptom recurrence
due to inadequate clot evacuation. Postprocedure management includes analgesics and
sitz baths. A retrospective review of 231 patients who received excision versus conservative
management of thrombosed hemorrhoid showed that time to symptom resolution averaged
24 days in the conservative group versus 3.9 days in the surgical group.[18]
In the nonemergent setting, popular procedures performed in the operating room include
hemorrhoidectomy, stapled hemorrhoidopexy, and Doppler-guided hemorrhoidal artery
ligation.
Hemorrhoidectomy
There are two major types of hemorrhoidectomy: Ferguson, or closed hemorrhoidectomy
and the Milligan–Morgan, or open hemorrhoidectomy. The open hemorrhoidectomy is often
the preferred approach to surgically treat severe acute gangrenous hemorrhoids where
tissue edema and necrosis preclude closure of the mucosa ([Fig. 3]).[19] Preoperatively, full mechanical bowel prep is not indicated. Additionally, there
is no benefit to perioperative antibiotic administration.[20]
Fig. 3 Open (Milligan–Morgan) hemorrhoidectomy. Panel A: external hemorrhoid is grasped.
Panel B: internal hemorrhoid is grasped. Panel C: external skin and hemorrhoids excised.
Panel D: tie placed around the hemorrhoid vascular bundle. Panel E: ligation of the
vascular bundle. Panel F: excision of the hemorrhoid tissue distal to the tie. (Reprinted
with permission from Cintron J, Abcarian H. Benign anorectal: hemorrhoids. In: The
ASCRS Textbook of Colon and Rectal Surgery. New York, NY: Springer-Verlag, Inc; 2007:156–77;
with kind reprint permission of Springer Science + Business Media.).
An excisional hemorrhoidectomy typically begins with the injection of a local anesthetic,
often containing epinephrine to help with bleeding and swelling. After a Hill–Ferguson
retractor is placed into the anal canal for exposure, the junction of the internal
and external component of the hemorrhoid is grasped and serves as a handle to retract
the hemorrhoid away from the sphincter muscles. An elliptical incision is made, and
the hemorrhoid tissue is carefully dissected away from the superficial internal and
external sphincter muscles to the main vascular pedicle in the anal canal, carefully
avoiding any injury to the anal sphincters. The base of the pedicle is ligated and
the hemorrhoid is excised. Devices using advanced energy, such as ultrasonic shears
or a bipolar vessel sealant, can be used to perform this procedure with similar efficacy.[21]
Operative hemorrhoidectomy is a relatively morbid procedure compared with other less-invasive
options. Due to the extent of dissection and the presence of incisions below the dentate
line, postoperative pain can be severe, and may delay return to normal activities
for several weeks. Pain can usually be managed with oral analgesics, avoidance of
constipation, and sitz baths. Bleeding may occur in 1 to 2% of patients after 1 week
from surgery as a result of eschar separation and is usually self-limited.[22] Infection is uncommon after hemorrhoid surgery with submucosal abscesses occurring
in less than 1% of cases and severe fasciitis or necrotizing infections are rare.[22] Urinary retention has been reported to be as high as 34% after hemorrhoidectomy,
which is attributed to pelvic floor spasm, narcotic use, and excess intravenous fluids.[23] Treatment for urinary retention after hemorrhoidectomy is temporary Foley catheter
insertion with self-resolution in majority of cases. Injury to the sphincter resulting
in fecal incontinence occurs in 2 to 10% of cases and can have significant impact
on quality of life.[24] Lastly, anal stenosis is a late complication that can result from excessive tissue
resection or aggressive suturing. Stenosis is more common with multiple excised quadrants;
it is often difficult to treat and should be diligently avoided by assuring adequate
mucosal bridges between the excised hemorrhoids.
Despite its relative higher morbidity, surgical hemorrhoidectomy is more effective
than band ligation for preventing recurrent symptoms.[16] In a randomized trial among elective cases, there were no differences in open versus
closed hemorrhoidectomy.[25] Patients with grade III and IV hemorrhoids benefit the most from surgical hemorrhoidectomy.
Stapled Hemorrhoidopexy
An alternative to operative hemorrhoidectomy is stapled hemorrhoidopexy, in which
a stapling device is used to resect and fixate the internal hemorrhoid tissues to
the rectal wall. Since the staple line is above the dentate line, patients typically
experience less pain than those who undergo hemorrhoidectomy. To perform this procedure,
a circular stapler is introduced into the anus and prolapsing tissue is brought into
the stapler. The most critical component of stapled hemorrhoidopexy is the placement
of a circumferential, purse-string, nonabsorbable suture in the submucosa far enough
away to avoid any sphincter muscle involvement—usually at ∼4 cm from the dentate line.
Additionally, before engaging the stapler, an examination of the posterior vaginal
wall should be conducted. Finally, the staple line should be evaluated for any bleeding
that would require additional suture ligation.
Complications from stapled hemorrhoidopexy include bleeding from the staple line,
incontinence for injury of the sphincter muscles, and stenosis from incorporation
of excess rectal tissue. Moreover, there is a risk of recto-vaginal fistula in women
due to incorporation of vaginal tissue into the purse-string.
Three systematic reviews concluded that stapled hemorrhoidopexy was less effective
than conventional hemorrhoidectomy.[26]
[27]
[28] Stapled hemorrhoidopexy was associated with a higher long-term risk of hemorrhoid
recurrence. Due to need for additional operations, the incidence of prolapse and tenesmus
was also higher after stapled hemorrhoidopexy as compared with hemorrhoidectomy. Conversely,
the stapled approach was associated with significantly less pain, shorter operative
time, and shorter time to resumption of normal activity. In a 2010 European multicenter
randomized trial of stapled hemorrhoidopexy versus hemorrhoidectomy, both options
were shown to be equally effective in preventing recurrence after 1 year. Patients
undergoing hemorrhoidectomy were more likely to have symptomatic relief from the hemorrhoids
(69 vs. 44%), but had significantly greater postoperative pain.[29]
Overall, stapled hemorrhoidopexy remains a viable alternative to hemorrhoidectomy,
and is especially attractive for patients without much external disease. However,
while the published complication rates are low, they can be quite severe, and the
surgeon must have appropriate training and proceed with great caution, when performing
this procedure.
Doppler-guided Hemorrhoidal Artery Ligation
First described by Morinaga et al in 1995, this technique involves use of Doppler
ultrasound to identify and ligate the hemorrhoidal arteries.[30] This is also referred to as transanal hemorrhoidal dearterialization (THD). Different
platforms with different associated nomenclatures exist for this technique, but the
principles include the use of a Doppler probe to identify the six main feeding arteries
within the anal canal, ligation of these arteries with absorbable suture and a specialized
anoscope, and then plication of redundant hemorrhoidal mucosa. The plication is often
referred to as recto-anal-repair, mucopexy, or hemorrhoidopexy. Proposed benefits
of this procedure are similar to stapled hemorrhoidopexy, with less associated pain
due to the suturing being above the dentate line.
Early results of Doppler-guided hemorrhoidal artery ligation (DGHAL)/THD were promising,
with lower pain scores than hemorrhoidectomy, and relief of bleeding and tissue prolapse
in over 90% of patients.[31] Since then, several randomized clinical trials have been performed with mixed results.[32]
[33]
[34] Currently, DGHAL/THD remains a viable approach to multicolumn internal hemorrhoids.
However, the short-term benefits regarding postoperative pain have recently not been
as remarkable as in the earlier studies.
