Discussion
We report a series of patients with deep endometriosis involving the
sacral plexus or sciatic nerve, a complex disease which in a majority of
cases involves other major pelvic organs before reaching pelvic nerves.
The resulting diverse clinical presentations, due to multiple deep
endometriosis localisations, required complex surgical procedures
carried out by multidisciplinary surgical teams, with these procedures
related to a significant risk of postoperative complications. A year
after surgery, despite an overall improvement in pain and quality of
life and a high pregnancy rate by natural conception in half of the
cases, some patients experienced persistent bladder dysfunction and
neurological symptoms directly related to the surgical manipulation of
nerves. Due to the relative rarity of sacral and sciatic nerve
endometriosis, we believe that our data may provide additional helpful
information to existing knowledge available in the literature.
Our series has several weaknesses. Firstly it is a retrospective series
of patients receiving surgical management, without a control group. In
our practice we previously treated two patients for whom pelvic MRI
revealed deep endometriosis infiltrating pelvic wall and entrapping the
sacral plexus, and two others with deep endometriosis of the lumbosacral
space involving the sciatic nerve. All four patients received medical
treatment based on continuous contraceptive pill intake resulting in
prolonged amenorrhea, and consider their residual symptoms and quality
of life as satisfactory. These patients are however not included in the
CIRENDO database as they have not had surgery in our department.
Furthermore their endometriosis localisations have not intraoperatively
been confirmed and the patient number is too small to allow any
comparison with the cohort of women who benefited from surgery. Due to
the lack of control group, we cannot definitively state that deep
endometriosis removal leads to a significant improvement in pain and
quality of life when compared to continuous medical treatment, though
all 52 women underwent surgery due to the lack of efficacy of previous
medical therapies.
The second limit is related to the heterogeneity of multiple deep
endometriosis localisations recorded in our series and difficulties in
demonstrating a precise relationship between specific localisations and
corresponding symptoms. Accordingly baseline severe constipation may be
attributed to mid/low rectum infiltration by deep endometriosis, or to
splanchnic nerves or sacral root S2-S4 involvement; while postoperative
constipation may result from postoperative low rectal resection syndrome
(LARS)12 or rectal denervation following extensive
removal of parametrium together with splanchnic
nerves6. Consequently, assessment of the true
efficiency of nerve surgical management on pelvic organ function may be
challenging.
Our series presents however several strengths. This is a case-series
including consecutive patients with strict inclusion criteria and
prospective recording of preoperative, intraoperative and postoperative
data, employing standardised questionnaires to assess pelvic pain,
digestive and urinary function and quality of life. There is no loss to
follow up. Inclusion criteria limited enrolment to only women for whom
deep endometriosis nodules were in close contact with the sacral plexus
or sciatic nerve, requiring specific nerve dissection or excision. Our
results cannot therefore be overestimated by inclusion of women with
neurological complaints associated with a less severe disease. All
procedures were fully recorded and are available for review, and 5
procedures were broadcasted live during surgical meetings.
Our study provides detailed data on intraoperative findings and
postoperative outcomes in patients managed for deep endometriosis
involving large pelvic nerves. Due to the low prevalence of these
localisations, clinical study available in the literature tends to rely
on case-series, despite the afore-mentioned design weaknesses. The
pooling of information reported by several surgical teams allows to
further knowledge in this field and may be helpful for colleagues
interested in the management of such patients.
Deep endometriosis infiltrating large pelvic nerves has been described
as far back as 195513, but it was 50 years later that
the first description of a laparoscopic approach to release the sacral
plexus and sciatic nerve with deep endometriosis involvement was
reported5. Successive case-series confirmed overall
pain improvement in patients having benefited from surgery. The first
large case series including 27 women with isolated endometriosis of the
sciatic nerve and 148 women with deeply infiltrating parametric
endometriosis with sacral plexus infiltration, was published by Possover
et al2, and recorded a decrease in mean VAS pain score
from 7.7 to 2.6. Later, the Negrar Hospital team (Verona, Italy)
published several technical reports, focusing on the anatomy of pelvic
nerves and the nerve-sparing technique3,14. Lemos et
al reported on their experience in the management of 13 women with deep
endometriosis responsible for the entrapment of lumbosacral plexus, and
noted an overall improvement in 6 patients, while 6 other women were
completely pain-free1. More recently, Possover et al
reported a series of 46 women managed for intraneural endometriosis of
the sciatic nerve which required resection of more than 30% of the
nerve. Follow up continued over 5 years and revealed significant pain
reduction and recovery of nerve function4.
Deep endometriosis nodules involving sacral roots differ from those of
the sciatic nerve. Firstly, there is a higher prevalence of sacral roots
involvement representing 94.2% of cases in our series and 85% (148 out
of 175 cases) for Possover et al2. Secondly sacral
roots entrapment appears to be much more frequent than actual nerve
infiltration, due to the posterior development of large rectovaginal or
parametrial nodules. Conversely, intraneural endometriosis was more
frequently reported in sciatic nerves and may require partial resection
of the nerve4.
Although pain reduction may occur early after surgery, various sensory
or motor complaints may continue over months or years. When
preoperatively affected, motor function recovery is long, and normal
gait may take up to 5 years to restore4. Nerve
entrapment or infiltration by fibrous endometriosis nodules require
meticulous nerve dissection, excision of epineurium, fibre manipulation,
as well as repeated haemostasis procedures responsible for thermal
diffusion into the nerve, oedema and limited ischemia. These
circumstances unavoidably lead to neuropraxia15followed by postoperative sensory, motor or vegetative temporary
disorders. Neuropraxia refers to mild nerve injury involving impairment
of both motor and sensory functions and is the first type of peripheral
nerve injury according to the Seddon and Sunderland
classification16,17 with no loss of axon but a
temporary loss of myelin sheath. This demyelination leads to impairment
of impulse conduction across the nerve segment15without Wallerian degeneration. The prognosis is favourable with
complete recovery likely within weeks or months, due to axon
remyelination18. Transitory bladder dysfunction
requiring self-catheterisation for 4 to 6 weeks is a common clinical
outcome of neuropraxia involving sacral or splanchnic nerves, and
provides an explanation for bladder function recovery in three quarters
of our patients with routine self-catheterisation during the early
postoperative period. Administration of neuroleptic agents and
postoperative physiotherapy play a key role in improving nerve
recovery4.
However, neuropraxia is unlikely to be the most severe complication
recorded in patients managed for deep endometriosis of the sacral
plexus, particularly when the disease also involves low rectum, vagina
or ureters. Concomitant rectal excision may be followed by specific
complications such as rectovaginal fistula or low anterior rectal
resection syndrome (LARS)12. Although our rectovaginal
fistula rate may be considered high, it remains comparable to that
reported in other series of patients undergoing low rectal resection for
deep endometriosis associated with colpectomy19. The
high rate of vaginal involvement requiring colpectomy also led to the
relatively high prevalence of early postoperative pelvic abscess and
frequent use of preventive stoma.
Nerve-sparing surgery, commonly applied in oncology for preservation of
autonomic nerves, has been shown to improve quality of life by reducing
the incidence of functional complications without compromising long-term
survival20. The approach has to be tailored to suit
surgical management of deep infiltrating endometriosis, which differs
from cancer14,21. In cases where surgical indication
exists for the treatment of early cancer, this approach works in
disease-free tissue where nerves are not involved by the disease and may
thus be easily separated and preserved. Conversely, preservation of the
inferior hypogastric plexus is not possible and has to be sacrificed in
patients who present with large infiltrations of the parametrium down to
the levator ani muscles and sacral plexus. As performing small nerve
sparing in large nodules of the parametrium is not feasible, bladder or
rectal functional impairment may only be avoided by preserving the
contralateral inferior hypogastric plexus, hypogastric and splanchnic
nerves. In cases where endometriosis involves both parametria, surgeons
tend to favour perfroming complete resection on the side with the more
aggressive disease, and lesser treatment on the contralateral side,
thereby preventing complete denervation of the bladder, rectum and
vagina1,2,21. While unilateral sacrifice of small
pelvic nerves may be considered, the conservation of large sacral and
sciatic nerves remains a priority so as to avoid major sensory and motor
somatic troubles.
It should be noted that women with deep endometriosis involving the
sacral plexus and sciatic nerve in our series rarely had ovarian and
fallopian tubes localisations, their disease being mainly
sub-peritoneal. This resulted in an excellent pregnancy and delivery
rate as early as 1 year after the procedure, with natural conception in
half of the cases. This point is of particular importance, as a fear of
fertility impairment following a complex surgical management may lead to
unnecessarily privileging first line IVF in symptomatic patients with
such severe disease and pregnancy intention.
All authors recommend referring patients with deep endometriosis of the
sacral plexus and sciatic nerve to expert centres with high volume
activity4,14,22. This recommendation highlights
parameters which are important for ensuring the best outcomes: knowledge
of anatomy and laparoscopic approaches to the sacral plexus, the
availability of multidisciplinary teams for treatment of associated
localisations in the digestive and urinary tract, experience in surgical
procedures that ensure organ function preservation for each
localisation, an ability to perform surgery in a reasonable operative
time, and an ability to identify the early signs and symptoms of
potential postoperative complications and to accurately manage them
without delay. We believe this recommendation to be reasonable, despite
the present lack of a large multicenter series or randomized trial to
support it.
Study funding/competing interest(s): The North-West Inter
Regional Female Cohort for Patients with Endometriosis (CIRENDO) is
financed by the G4 Group (The University Hospitals of Rouen, Lille,
Amiens and Caen) and ROUENDOMETRIOSE Association. No financial support
was received for this study. The authors declare no competing interests
related to this study.