Surgery chapters
Principles of laparoscopic and robotic surgery
How minimal access surgery works, how a pneumoperitoneum is made and what it does to the body, the main complications and how to avoid them, and what robotic systems add.
- Laparoscopy uses a CO2 pneumoperitoneum (kept at or below about 15 mmHg) to create working space; CO2 is chosen because it is soluble and does not burn, but its absorption causes hypercapnia.
- The first port is placed by a closed (Veress needle) or open (Hasson) technique; the open method is safer after previous surgery, and blind entry carries the risk of bowel and major vessel injury.
- Robotic systems are master–slave platforms that add 3D vision, tremor filtering, motion scaling and wristed instruments, at the price of cost, set-up time and lost touch.
On this page
Overview
Minimal access surgery reaches the target organ through small ports instead of a large wound. The surgeon works from a video image using long instruments. Because the wound is the main source of pain, infection, hernia and slow recovery after open surgery, shrinking it gives faster recovery and shorter stay.
The main forms are laparoscopy (abdomen, with gas), thoracoscopy (chest; the rigid chest wall usually keeps the space open without gas), endoluminal endoscopy (inside hollow organs), perivisceral endoscopy (e.g. mediastinoscopy, retroperitoneoscopy, extraperitoneal hernia repair) and arthroscopy.
The core steps can be remembered as I-VITROS: Insufflate, Visualise, Identify, Triangulate, Retract, Operate, Seal.
Advantages and limitations
| Advantages | Limitations |
|---|---|
| Smaller wounds; less wound infection, dehiscence, bleeding, hernia and nerve entrapment | Remote, two-dimensional view; depth is hard to judge |
| Less pain, earlier mobility, fewer chest infections and less ileus | Loss of touch (tactile/haptic feedback) |
| Less heat and fluid loss from an open cavity | Demands hand–eye coordination; long learning curve |
| Fewer adhesions (less handling of serosa) | Bleeding is hard to control (blood absorbs light and fills a small field) |
| Magnified view; earlier return to work | Large specimens must be bagged and extracted; longer operating times at first |
Converting to open surgery is not a complication. It is a judgement made for patient safety, and the risk of conversion must be part of the consent.
The pneumoperitoneum
Why carbon dioxide?
- Highly soluble in blood, so small amounts entering a vessel are absorbed quickly (less risk of fatal gas embolism than air).
- Does not support combustion, so diathermy is safe.
- Cheap and easily excreted by the lungs.
The downside is that CO2 is absorbed from the peritoneum, raising arterial and end-tidal CO2.
Pressure and flow
Gas is started at low flow (about 1–4 L/min) and then increased, with the pressure capped at about 15 mmHg (common working range 12–15 mmHg). In thoracoscopy, when gas is needed, much lower pressures (about 5–8 mmHg) are used. In children, pressures are reduced to suit size.
Physiological effects
| System | Effect of CO2 pneumoperitoneum |
|---|---|
| Respiratory | Diaphragm pushed up: less FRC and compliance, higher airway pressure, basal atelectasis; hypercapnia and respiratory acidosis from CO2 absorption |
| Cardiovascular | Raised systemic vascular resistance and blood pressure; at higher pressures IVC compression lowers venous return and cardiac output; arrhythmias; peritoneal stretch may cause vagal bradycardia |
| Renal | Lower renal blood flow and urine output |
| Venous | Reverse Trendelenburg and raised abdominal pressure cause venous stasis → DVT risk |
| Brain | Hypercapnia and steep head-down tilt raise intracranial pressure |
In an MCQ on the effects of pneumoperitoneum, the safe single answer is hypercapnia (raised end-tidal CO2). Severe COPD and ischaemic heart disease may be relative contraindications because these patients tolerate the CO2 load and cardiac changes poorly.
Getting into the abdomen (first port)
| Method | How | Notes |
|---|---|---|
| Closed (Veress needle) | Spring-loaded needle with a blunt inner stylet is passed blindly at the umbilicus, then gas is run in before the first trocar | Quick, but small risk of bowel or major vessel injury; check the bladder is empty first |
| Open (Hasson) | Small incision at the umbilicus, fascia opened under vision, finger confirms entry, blunt Hasson trocar fixed with stay sutures | Avoids blind puncture; preferred by most general surgeons; safest after previous surgery |
| Optical entry | Bladeless see-through trocar with the camera inside, layers seen as they are passed | Popular in morbid obesity (bariatric surgery) |
| Palmer's point | Entry 3 cm below the left costal margin in the midclavicular line | Used when umbilical adhesions are likely (previous midline scars) |
Confirming the Veress needle is in the peritoneal cavity
Gas should not be turned on until:
- two "clicks" (or losses of resistance) are felt as the needle passes the fascia and then the peritoneum;
- aspiration through the needle brings back no blood or bowel content;
- the saline drop test is positive: a drop of saline on the hub falls in freely;
- the opening pressure is low and gas flows easily.
A high opening pressure with poor flow means the tip is preperitoneal, in omentum or in bowel; stop and reposition, do not keep insufflating.
Special situations
- Previous abdominal surgery: no longer a contraindication. Use the open technique away from scars, sweep away adhesions with a fingertip and the camera.
- Obesity: thick fat makes entry harder; a longer needle, entry above the umbilicus at a near right angle, longer instruments or optical entry help.
- Very thin or kyphotic patients: aorta and iliac vessels lie close to the umbilicus.
Preoperative preparation
- Fitness for general anaesthesia and for open surgery if conversion is needed.
- Check coagulation: uncorrected coagulopathy (e.g. cirrhosis) is a contraindication; stop warfarin or switch to heparin.
- Note previous scars, body habitus, cardiac and lung disease.
- Thromboprophylaxis: LMWH, stockings and intraoperative calf compression.
- Informed consent: include conversion to open, shoulder tip pain, minor surgical emphysema, and rare serious injury (bile duct, bowel, vessels).
Intraoperative complications
Bleeding
Bleeding is the commonest reason for conversion to open surgery. Higher risk: cirrhosis, acute inflammation (cholecystitis, diverticulitis), antiplatelet drugs, coagulation defects.
- Major vessel: press with a blunt instrument or swab, suction and irrigate, add a port, clip or coagulate; convert early if control is uncertain.
- Port site: press with the trocar; suture the vessel; a Foley balloon pulled up against the wall can tamponade an inferior epigastric bleed.
Visceral injury
Bowel or vessel injury happens mostly at blind entry or from trocars. Gallbladder perforation with spilled stones is more common laparoscopically: retrieve stones, use an extraction bag and wash out.
Electrosurgical (diathermy) injury
- Incidence about 1–2 per 1000 operations; almost all from monopolar diathermy.
- Usually unnoticed at the time; patients present 3–7 days later with fever and abdominal pain (delayed perforation).
- Mechanisms: touching tissue by mistake, direct coupling (active probe touches another metal instrument), insulation breaks, sparking, capacitive coupling, and current through recently coagulated tissue.
- Prevention: prefer bipolar or ultrasonic devices, keep all live tips in view, use low power, check insulation.
Gas-related problems
Surgical emphysema, pneumothorax or pneumomediastinum, and rarely CO2 gas embolism (sudden hypotension, fall in end-tidal CO2, "mill-wheel" murmur): stop gas, release pneumoperitoneum, left side down and head down, aspirate through a central line.
Postoperative care
| Problem | Key points |
|---|---|
| Shoulder tip pain | Referred from diaphragmatic irritation by CO2 (phrenic nerve, C3–C5); worst at about 24 hours; settles in 2–3 days with paracetamol |
| Nausea | About half of patients; ondansetron; avoid opioids |
| Port site pain | Usually settles fast; increasing pain after 2–3 days suggests infection or a port-site (often Richter) hernia |
| Severe pain, fever or tachycardia | Something is wrong (bile leak, bowel or diathermy injury): FBC, CRP, LFTs, amylase, ultrasound, ERCP if bile leak; re-look early |
A patient who is getting worse after a routine laparoscopic operation needs early senior review and a low threshold for relaparoscopy. Deaths after technical errors are linked to delay in going back.
- Oral fluids from about 4–6 hours; most are fit for discharge within 24 hours; average return to work about 10 days.
- Close the fascia at larger port sites to reduce port-site hernia.
Other uses of laparoscopy
- Diagnostic laparoscopy: unexplained pain, suspected abdominal tuberculosis (biopsy of peritoneal tubercles), stable trauma, infertility.
- Staging laparoscopy: for gastric, oesophageal, pancreatic and ovarian cancer. It finds peritoneal seedlings (transcoelomic spread) and small liver metastases missed on CT; laparoscopic ultrasound helps.
- Emergencies in stable patients: appendicectomy (commonest), perforated duodenal ulcer repair, acute cholecystitis, adhesive obstruction.
Robotic surgery
Current systems are master–slave: the surgeon sits at a console (master) and controls robotic arms (slave) that hold the camera and instruments. The best known platform is da Vinci. Robots are used most in pelvic surgery (prostatectomy, rectal and gynaecological surgery), and also in cardiac, thoracic, ENT and paediatric surgery.
| Advantages for the surgeon | Disadvantages |
|---|---|
| Magnified 3D stereoscopic view | High cost of the system and instruments |
| Tremor filtering | Longer set-up and operating time |
| Motion scaling (large hand movement → small instrument movement) | No haptic feedback |
| Wristed instruments with up to 7 degrees of freedom | Long learning curve; arm collisions; repeated docking |
| Comfortable seated position; remote operation possible | Conversion still needed at times; limited availability |
Pooled studies show less blood loss and transfusion with robotic surgery than with open or laparoscopic surgery, and shorter stay and fewer complications than open surgery, but longer operating times and variable cost-effectiveness.
Steep head-down tilt for several hours (robotic prostatectomy, some bowel operations) can cause myocardial ischaemia, raised intracranial pressure and high airway pressures; choose patients carefully.
Newer approaches
- Hand-assisted laparoscopy: a hand inside through a small incision while gas is maintained; allows palpation and finger pressure on bleeders.
- Single-incision laparoscopic surgery (SILS): all instruments through one multichannel port at the umbilicus; better cosmesis, harder ergonomics.
- NOTES (natural orifice transluminal endoscopic surgery): entry through the stomach, vagina or colon (e.g. transvaginal cholecystectomy); safe closure of the visceral opening is the main unsolved problem.
Expect: why CO2 is used and its effects (hypercapnia, raised SVR, fall in venous return at high pressure), safe insufflation pressure, safety checks before insufflating through a Veress needle, open (Hasson) entry and Palmer's point after previous surgery, bleeding as the commonest reason for conversion, delayed diathermy injury from monopolar current, shoulder tip pain, staging laparoscopy finding peritoneal seedlings, and the pros and cons of robotic master–slave systems.
Quick revision
- Gas: CO2; pressure up to about 15 mmHg; start at low flow.
- Effects: hypercapnia, acidosis, raised SVR, less venous return at high pressure, less FRC, DVT risk.
- Closed entry = Veress (two clicks, aspiration, drop test, low pressure); open entry = Hasson.
- Previous scars: open entry or Palmer's point (left upper quadrant).
- Bleeding is the main cause of conversion; conversion is good judgement.
- Monopolar diathermy injury: unseen, presents day 3–7.
- Shoulder tip pain = diaphragmatic irritation; settles in 2–3 days.
- Robot: master–slave, 3D, tremor filter, motion scaling, 7 degrees of freedom; costly, no touch.
Written by The House Job from standard references (Bailey & Love).
FAQ
Why is carbon dioxide used instead of air for laparoscopy?
It is very soluble, so any gas that enters a vessel dissolves quickly, and it does not support combustion when diathermy is used. Its absorption, however, raises blood CO2.
What is the safest way to enter the abdomen in a patient with a previous midline laparotomy?
An open (Hasson) cut-down away from the scar, or entry at Palmer's point in the left upper quadrant, rather than a blind Veress needle at the umbilicus.
Why does shoulder pain occur after laparoscopy?
Residual CO2 irritates the undersurface of the diaphragm, and the pain is referred along the phrenic nerve (C3–C5) to the shoulder tip.
What is the main disadvantage of robotic surgery?
Its high cost and longer set-up and operating time; the surgeon also loses the sense of touch.