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Anatomy + Caesarean Section Rishita PrabhuThanks to our partners!Anatomy Learning Objectives: ● Describe the origins, courses and relations of the uterine and ovarian arteries ● Describe the three parts of the uterus ● Describe the anatomical position of the uterus (anteverted vs anteflexed) ● Describe the tissue layers that make up the uterus ● Recognise the ligaments that support the uterus Uterus Fundus • Secondary sex organ. • Functions: • Maintain and transport gametes • Facilitates embryonic and foetal development. • Facilitates with expulsion of the foetus. Body Cervix • 3 Parts: • Fundus: Entry point of uterine tubes. • Body: Site of implantation of blastocyst. • Cervix: Links the uterus to the vagina. Layers of the Uterus • 3 Layers of the uterus: • Perimetrium • Myometrium • Endometrium Endometrium • Deep stratum basalis Perimetrium • Superficial stratum functionalis Myometrium Superficial stratum functionalis Deep stratum basalis Ligaments of Uterus • Ligaments supporting the Fundus and Body: • Broad ligament: Attaches the uterus to the lateral pelvic walls. • Mesosalpinx: Supports the fallopian tubes. • Mesometrium: Supports the fundus and body of the uterus. • Mesovarium: Supports the ovaries. • Round ligament • Ligaments supporting the cervix: • Pubocervical ligament • Cardinal/ transverse cervical ligament • Uterosacral ligament • Ovarian ligament: Connects the ovary to the uterus. Positioning of the uterus • Based on position of the body: • Anteflexed: Body points anteriorly • Retroflexed: Body points posteriorly • Based on position of the cervix: • Anteverted: Cervix points anteriorly • Retroverted: Cervix points posteriorly An individual with a retroverted positioning is at risk of developing a uterine prolapse. Why? • A retroverted cervix leads to the uterus being directly above the vagina. So, if there is increased intra-abdominal pressure, it can increase the chances of the uterus prolapsing into the vagina. Anteverted Anteverted Retroverted Retroverted Anteflexed Retroflexed Anteflexed Retroflexed Vascular Supply of the Uterus • Blood supply: Uterine arteries • Venous drainage: Plexus of the broad ligament → Uterine vein → Internal iliac vein The uterine artery The ovarian artery originates originates from the from the abdominal aorta anterior branch of the slightly below the renal internal iliac artery. It runs artery. It runs through the within the broad ligament suspensory ligament and and supplies the uterus. supplies the ovary. What is the relationship between the uterine artery and ovarian artery? They form an anastomotic network to provide collateral circulation to the uterus.Caesarean Section Learning Objectives: ● Describe the paths and innervations of the pudendal nerves and the sites that may be injected for anaesthesia during childbirth ● Describe the layers of the abdomen that are dissected in a c-section ● Discuss how emergency c-sections are subclassified based on urgency ● Discuss the indications for c-section (e.g. breech, malpresentations, twins, foetal compromise, maternal medical conditions etc) ● Recognise why elective c-sections are typically scheduled after 39 weeks and the role of corticosteroids prior to this ● Describe pre-operative management (FBC and group & save, Proton Pump Inhibitor, VTE prophylaxis) ● Discuss anaesthetic options ● Describe a c-section with mention of different incision options ● Discuss the possible immediate, intermediate and late complications following a c-section Pudendal Nerve • Arises from S2, S3 and S4 from the sacral plexus. • Provides sensory and somatic innervation to the external genitalia and vagina. • Branches: Inferior rectal nerve, perineal nerve, and dorsal nerve of the clitoris. Clinical relevance: • Pudendal nerve block is used as pain relief during the second and third stage of labour for normal and instrumental delivery and episiotomy. • A vaginal examination is performed to identify the location of the pudendal vessels. • The block should be assessed clinically prior to an episiotomy or insertion of forceps. Indications of a Caesarean Section Uterine/Anatomical Maternal Indications Indications Foetal Indications Previous C-Section Placenta praevia Malpresentations Previous perineal trauma Placental abruption* Twin pregnancy Herpes simplex or Genital tract Foetal HIV infection obstructive mass compromise* Medical conditions such as Cervical cerclage Macrosomia cardiomyopathy Invasive cervical Umbilical cord Maternal request cancer prolapse* *Indications of an emergency Caesarean Section Elective Caesarean Sections At what gestational age are elective Caesarean sections usually planned? • After 39 weeks • An elective Caesarean section is usually planned after 39 weeks to reduce the risk of respiratory distress. • Most common type of neonatal respiratory distress is Transient Tachypnoea of the Newborn (TTN). • Transient Tachypnoea of the Newborn: A delay in clearing amniotic fluid from the lungs. If a Caesarean section needs happen prior to 39 weeks, what might be given to the mother to prevent respiratory distress? • Corticosteroids to stimulate the production of surfactant. Emergency Caesarean Sections • What are some common reasons an emergency Caesarean Section might be done? • Failure to progress in labour. • Suspected/confirmed foetal compromise. Category Description Situations • For a category 1 section, the Immediate threat to the life Placental abruption, umbilical baby should be born within 1 of the woman or foetus. cord prolapse. 30 mins. • For a category 2 section, the Maternal or fetal Non-reassuring foetal heart baby should be born within 2 compromise that is not rate, preeclampsia. 75 mins. immediately life-threatening. No maternal or fetal Poorly controlled 3 compromise but needs early hypertension, delivery. chorioamnionitis. Elective – delivery timed to Previous Caesarean section, 4 suit woman or staff. maternal request. Preoperative management • Gain informed consent • Optimisation of maternal comorbidities in case of an elective caesarean section. • Full blood count • Group and Save: Determine blood group and screens for any atypical antibodies. • Proton Pump Inhibitor/H2 receptor antagonist: Reduces gastric acid secretion and hence the risk of aspiration pneumonitis. • VTE prophylaxis: Risk should be calculated. Anti- thromboembolic stockings +/- LMWH should be used appropriately. What complications does severe anaemia increase the risk of during pregnancy and birth? • Pregnancy: Pre-eclampsia, placental abruption and cardiac failure. • Birth: Pre-term labour, low birth weight, iron deficiency in babies. Anaesthesia • Regional anaesthetic (A combination of local anaesthetic and an opioid): • Spinal anaesthetic: The medication is directly injected into CSF. Usually requires lower doses which lowers complication from the medication. • Epidural: The medication is injected into the epidural space which diffuses through the dura into CSF. • General anaesthetic: The patient is unconscious during the surgery. Indications: • Failure of regional anaesthesia At what spinal level is an epidural • Contraindication to regional anaesthetic administered? • Need to expedite delivery (often occurs for • L2/L3 or L3/L4 which is after the Category 1 Caesarean Sections). conus medullaris where mobile • Once the anaesthetic is ready, a foley catheter is spinal nerves are present. This placed to drain the bladder. This reduces the risk of lowers the chance of neurological bladder injury during the procedure. damage. Procedure The patient is positioned with a left lateral tilt of What might be administered to aid with 15°to reducethe risk of supinehypotension. Whymight this occur? placental delivery? • Aortocavalcompression • Oxytocin • Skin incision • Transverse • Pfannensteil: Curvilinear incision 2 cm above the pubic symphysis. Subsequent layers of the abdomen are accessed by sharp incision. • Joel Cohen: Straight line 3 cm above the pubic symphysis. Subsequent layers of the abdomenare accessed bluntly (Midline of fascia is incised and bluntly stretched). • Vertical: Used in emergencies, better exposure. • Abdominal incision: Sharp/Blunt • Uterine incision: • Low transverse incision: Incision in the lower uterine segment. Most common and a lower risk of uterine rupture. Vertical Low Low • Vertical incision: Incision vertically along the midline. Only used in certain situations like incision vertical transverse needing to quickly access the baby, placenta praevia. Increased risk of rupture. incision incision • Low vertical incision: Vertical incision in the lower uterine segment. Used if there is limited space to access the lower uterine segment. Layers of the abdomen • Skin • Subcutaneous tissues • Fascia • Camper’s fascia • Scarpa’s fascia • Rectus sheath • Aponeurosis from the external oblique rectus muscle • Fused layer that consists of the aponeuroses of the transverse abdominis and internal oblique muscles • Rectus abdominis The visceral peritoneum is incised and • Parietal peritoneum pushed down to expose the bladder. • Visceral peritoneum • Uterus The bladder is retracted by the Doyen retractor. Complications Stage Complications • Postpartumhaemorrhage (>1000ml) • Wound haematoma Immediate • Intra-abdominal haemorrhage (Within 24 hours) • Bladder/bowel trauma • Neonatal: • Transient tachypnoea of the newborn • Foetal lacerations (1-2% risk). • Infections: Intermediate • Urinary tract infection (24 hours – 1 week) • Endometritis • Respiratoryinfection • Venous thromboembolism • Urinary tract trauma (fistula) • Subfertility (there is a delay in conceiving compared to women who have had vaginal deliveries) Late • Regret and other negative psychological sequelae • Rupture/dehiscence of scar at next labour (VBAC) • Placenta praevia/accreta • Caesarean scar ectopic pregnancy Post Partum Haemorrhage • Classification • Minor: 500-1000 ml • Major: >1000 ml • Moderate: 1000-2000 ml • Severe: >2000 ml • Management: • ABCDE approach • Aim for 94-98% O2 saturation, give 15L/min of oxygen if required. • Check temperature every 15 mins • Set up 2 points of IV access: • Give: Provide blood products and warm IV fluids, give uterotonics. • Take: 20 ml of venous blood for FBC, clotting screen and cross-match 4 units, serial ABG and VBG (every 15-30 mins). • 4 T’s: Tone, Tissue, Trauma, Thrombin • Rub-up contractions, Bimanual compression • Controlled cord traction if placenta isn’t delivered Question 1 A 30-year-old woman presents to the GP with menstrual cycle irregularities and abdominal discomfort. Physical examination reveals a pelvic mass and she is subsequently referred to a gynaecologist. Following a transabdominal ultrasound, she is found to have a fibroid in a structure attaching the uterus, fallopian tubes and ovaries to the pelvic wall. Which ligament is this? a) Broad Ligament b) Round Ligament c) Pubocervical ligament d) Cardinal/ transverse cervical ligament e) Uterosacral ligament Answer: Broad Ligament It attaches the fundus and body to the lateral walls of the pelvis. The pubocervical, cardinal and uterosacral ligament all support the cervix. Question 2 A 27-year-old woman, who is 20 weeks pregnant, presents to her GP with complaints of sharp, intermittent pelvic pain on the right side that occasionally radiates to her groin and is exacerbated by physical activity. The doctor considers that the pain may be attributable to the stretching of a ligament that connects the uterus to the labia majora, which is commonly affected during this stage of pregnancy. What ligament is most likely responsible for her symptoms? a) Broad Ligament b) Round Ligament c) Pubocervical ligament d) Cardinal/ transverse cervical ligament e) Uterosacral ligament Answer: Round Ligament It runs from the uterine cornua to the labia majora. The pubocervical, cardinal and uterosacral ligament all support the cervix. Question 3 A 60-year-old woman attends the GP with symptoms suggestive of a vaginal prolapse. On internal examination, it is found that the uterus has prolapsed into the vagina. What is the normal anatomical position of the uterus? a) Retroverted and retroflexed b) Retroverted and anteflexed c) Anteverted and retroflexed d) Anteverted and anteflexed Answer: Anteverted and anteflexed The uterus is normally anteverted and anteflexed in the majority of women. Question 4 Mrs. Smith, a 32-year-old G2P1 woman at 38 weeks of gestation with gestational diabetes and decreased fetal movements over 24 hours. Which category of an emergency Caesarean section does she fall under? a) Category 1 b) Category 2 c) Category 3 d) Category 4 Answer: Category 2 While there is no immediate threat to the life of the woman or fetus, concerns regarding decreased fetal movements and the presence of gestational diabetes requires assessment and delivery within 75 minutes. Question 5 Mrs. Smith, presents to the GP a year later with a sensation of heaviness and 'dragging' consistent with prolapse. A ligament that runs between the cervix and lateral pelvic wall has been damaged. What is the name of the affected ligament? a) Broad Ligament b) Round Ligament c) Pubocervical ligament d) Cardinal/ transverse cervical ligament e) Uterosacral ligament Answer: Cardinal/transverse cervical ligament The cardinal ligament runs between the cervix and the lateral pelvic wall. The pubocervical ligament connects the cervix to the posterior aspect of the pubic bone. The uterosacral ligament connects the cervix and posterior vaginal dome to the sacrum. References • https://www.ncbi.nlm.nih.gov/books/NBK554736/ • https://www.ncbi.nlm.nih.gov/books/NBK470297/ • https://www.ncbi.nlm.nih.gov/books/NBK546707/ • https://www.ncbi.nlm.nih.gov/books/NBK542219/ • https://radiopaedia.org/articles/uterus?lang=gb • https://www.bradfordhospitals.nhs.uk/wp-content/uploads/2019/05/Pudendal-Nerve-Block.pdf • https://www.asahq.org/about-asa/newsroom/news-releases/2019/10/8-anemia-after-cesarean • https://oss-online.ca/knowledge-base/cs101-abd-entry/ • https://youtu.be/8ZzwNcVYEjY?si=Siljfs6exNuur3oT (Short demonstration on how a C-Section is done) • https://teachmeobgyn.com/labour/delivery/caesarean-section/ • https://www.nice.org.uk/guidance/ng192/chapter/Recommendations@supta_uk @SUPTAUK www.supta.uk