Classifications for the General Surgery Clinic

What you'll be asked across the desk, and what each one actually changes.

Clinic is where classifications earn their keep. A grade or stage is shorthand for a decision — which operation, which interval, which conversation with the patient. This reference gives you the system and the consequence.

Last reviewed: August 2026. Guidelines change. Check your trust protocol and current NICE/BSG/ACPGBI/AUGIS guidance before applying anything here to patient care.

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PART ONE — CROSS-CUTTING SYSTEMS

These come up in every clinic regardless of subspecialty.

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1. TNM — and the 9th Edition Change

The UICC TNM 9th edition took effect on 1 January 2026. Most people are still quoting the 8th. Knowing this is a cheap and reliable way to sound current.

• Major revisions in the 9th edition: head and neck (salivary gland, nasopharyngeal, HPV-related oropharyngeal), lung, thymoma, mesothelioma.
• More limited changes for colorectal, breast and most general surgical cancers — including a revised definition of tumour deposits in colorectal cancer.
• UK cancer registries and MDTs are transitioning; your trust may still be reporting in 8th edition. Say which edition you're using.

TNM prefixes — get these right

ypT0N0 after neoadjuvant chemoradiotherapy = pathological complete response. Strong prognostic marker in rectal and oesophageal cancer.

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2. ASA Physical Status

Add E for emergency: ASA IIIE.

ASA is about the patient, not the operation. Combine with procedure-specific risk and functional capacity.

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3. Performance Status (ECOG / WHO)

Determines fitness for oncological treatment. Comes up in every cancer clinic and MDT.

PS 0–1 — candidates for radical treatment and most chemotherapy. PS 2 — the grey zone; treatment often modified. PS 3–4 — generally best supportive care or palliative intent only.

The practical bedside question that separates 1 from 2: "Are you up and dressed for most of the day?"

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4. Clavien-Dindo — Post-operative Complications

The standard for grading complications in audit, research and consent discussions.

Suffix "d" if the patient has a persisting disability at discharge.

The Comprehensive Complication Index (CCI) aggregates all complications in a single patient into a 0–100 score — increasingly used in trials because Clavien-Dindo only captures the most severe event.

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5. Risk Scores

• P-POSSUM — Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity. Twelve physiological and six operative variables. Widely used but overestimates mortality in low-risk patients.
• NELA risk calculator — the standard for emergency laparotomy in the UK. NELA mandates that a documented risk assessment is made pre-operatively. Predicted mortality ≥5% should trigger consultant surgeon and consultant anaesthetist presence and consideration of critical care.
• SORT (Surgical Outcome Risk Tool) — quick pre-operative estimate for elective surgery.

Documenting a numerical risk estimate in the consent discussion is both good practice and exactly what Montgomery requires.

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PART TWO — BREAST CLINIC

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6. Triple Assessment Coding

Every breast clinic letter uses these. Each modality is scored 1–5 on the same logic: 1 = inadequate/normal, 5 = malignant.

B5 is subdivided: B5a = carcinoma in situ; B5b = invasive carcinoma. This distinction matters — B5a may not need axillary staging.

What the discordant results mean

• Triple assessment is concordant or it isn't. A P2 U2 B5 is discordant and the biopsy wins. A P4 U2 B2 is discordant and needs re-biopsy or excision — do not reassure on the strength of the two benign results.
• B3 is the difficult one — atypia of uncertain malignant potential. Includes atypical ductal hyperplasia, lobular neoplasia, papillary lesions, radial scar, phyllodes. Managed by vacuum-assisted excision or diagnostic excision, discussed at MDT. Upgrade rate to malignancy is meaningful.
• C3–C5 cytology should generally be followed by core biopsy — cytology cannot distinguish invasive from in situ disease.

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7. Nottingham Grade (modified Bloom-Richardson / Scarff-Bloom-Richardson)

Three components, each scored 1–3:

1. Tubule formation (>75% / 10–75% / <10%)
2. Nuclear pleomorphism (small uniform / moderate variation / marked variation)
3. Mitotic count (per 10 high-power fields, field-area adjusted)

Total 3–9:

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8. Nottingham Prognostic Index (NPI)

NPI = (0.2 × tumour size in cm) + lymph node stage (1–3) + grade (1–3)

Node stage: 1 = node negative; 2 = 1–3 nodes; 3 = ≥4 nodes.

Still quoted in UK breast MDTs, though PREDICT (the online tool incorporating age, ER, HER2, Ki67 and treatment modality) has largely superseded it for counselling patients about the benefit of adjuvant therapy.

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9. Receptor Status — the three that determine treatment

Triple negative (ER−, PR−, HER2−) — no targeted therapy available, chemotherapy is the mainstay, associated with BRCA1 and worse prognosis.

HER2-low (IHC 1+, or 2+ with negative ISH) is now a recognised category with implications for antibody-drug conjugates — worth knowing that the binary has softened.

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10. Breast Surgical Margins and Axillary Staging

• Invasive cancer: "no ink on tumour" is the internationally accepted margin; UK practice commonly uses ≥1 mm. NICE supports 1 mm.
• DCIS: ≥2 mm is the widely accepted standard.
• Sentinel lymph node biopsy for clinically and radiologically node-negative axilla.
• Positive SLNB with 1–2 macrometastases in a patient having breast conservation and whole-breast radiotherapy — axillary radiotherapy is equivalent to clearance (AMAROS), and completion clearance may be omitted altogether (Z0011).
• Isolated tumour cells (≤0.2 mm) and micrometastases (0.2–2 mm) generally do not mandate further axillary surgery.

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PART THREE — COLORECTAL CLINIC

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11. Hinchey Classification — Perforated Diverticulitis

The original is an operative/CT classification, but you will be asked in clinic when discussing interval management.

Modified Hinchey adds 0 (mild clinical diverticulitis) and subdivides Ia (confined pericolic inflammation) from Ib (pericolic abscess).

What it changes in clinic

• Uncomplicated diverticulitis — NICE supports no antibiotics in selected systemically well, immunocompetent patients without significant comorbidity. This surprises people.
• Routine interval colonoscopy after an episode of uncomplicated diverticulitis is no longer recommended — but is indicated after complicated diverticulitis (abscess, perforation) to exclude an underlying malignancy, usually at 6–8 weeks.
• Elective sigmoid colectomy is not indicated purely on the basis of number of attacks. Decide on the basis of ongoing symptoms, complications (stricture, fistula), immunosuppression and patient preference.

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12. Colorectal Cancer — TNM and Dukes

TNM (essentials)

A minimum of 12 lymph nodes should be examined for adequate staging. Fewer than 12 is a quality flag and may prompt upstaging of management.

Dukes (historical but still quoted)

Dukes never included stage D. If a consultant asks, that's usually the point they're testing.

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13. Rectal Cancer — MRI Staging

The single most important staging investigation in rectal cancer, and what the MDT actually discusses.

The three things the radiologist reports

1. T stage — with T3 subdivided by depth of extramural spread:

   • T3a <1 mm
   • T3b 1–5 mm
   • T3c 5–15 mm
   • T3d >15 mm

2. CRM (circumferential resection margin) — distance from tumour (or involved node or deposit) to the mesorectal fascia. Threatened or involved if ≤1 mm. This is the strongest predictor of local recurrence and the main determinant of neoadjuvant therapy.

3. EMVI (extramural venous invasion) — independent predictor of distant recurrence. EMVI-positive disease is treated more aggressively.

Height matters

• Low rectal tumours (<5 cm from anal verge) — risk to the sphincter complex; may need APER or intersphincteric resection.
• Mid (5–10 cm) and high (10–15 cm) — anterior resection with TME.

What drives neoadjuvant treatment

• Threatened CRM, T4, low tumours, EMVI positive, N2 → neoadjuvant long-course chemoradiotherapy.
• Short-course radiotherapy for downstaging in selected cases.
• Total neoadjuvant therapy (TNT) — chemoradiotherapy plus systemic chemotherapy before surgery — improves distant control and increases complete response rates.
• Watch and wait for clinical complete response after chemoradiotherapy is now an established option in specialist centres with rigorous surveillance.

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14. Parks Classification — Fistula-in-Ano

Defined by the relationship of the primary tract to the external anal sphincter.

What it changes

• Low fistulae (minimal external sphincter involvement) → fistulotomy, high success rate.
• High fistulae (significant sphincter involvement, anterior fistula in a woman, pre-existing incontinence, Crohn's) → sphincter-preserving approach: loose seton, LIFT (ligation of intersphincteric fistula tract), advancement flap, or fistula plug.
• Extrasphincteric fistulae are usually secondary — think Crohn's, malignancy, trauma, diverticular disease, or iatrogenic. Investigate the cause.
• MRI pelvis is the imaging modality of choice for complex, recurrent, or Crohn's-related disease.
• Always ask about continence before operating, and document it. This is the commonest source of litigation in benign anorectal surgery.

Goodsall's rule predicts the internal opening: anterior external openings track radially; posterior openings curve to the posterior midline. Less reliable anteriorly, in recurrent fistulae, and in Crohn's.

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15. Faecal Incontinence Scoring

St Mark's (Vaizey) score — 0–24

Seven items: incontinence to solid / liquid / gas, alteration of lifestyle (each 0–4 by frequency), plus need to wear a pad, use of constipating medication, and lack of ability to defer defaecation for 15 minutes (each 0 or 2–4).

0 = perfect continence; 24 = completely incontinent.

Wexner (Cleveland Clinic) score — 0–20

The same first five frequency items without the deferral and medication weighting. Simpler, widely used.

Both are worth using in clinic because they quantify change after treatment — essential for audit, and for a meaningful conversation with the patient about whether an intervention worked.

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16. Oxford Rectal Prolapse Grading (defaecating proctography)

Grades III–V correlate with symptoms; I–II are common in asymptomatic people and should not by themselves prompt surgery.

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17. Bristol Stool Chart

Deceptively useful — it converts a vague history into something you can track.

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18. Goligher — Haemorrhoids

Exclude a proximal source before attributing rectal bleeding to haemorrhoids — particularly with altered bowel habit, iron deficiency anaemia, age >40, or family history. Haemorrhoids are common; so is coexisting colorectal cancer.

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PART FOUR — HPB AND UPPER GI CLINIC

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19. Tokyo Guidelines 2018 (TG18) — Acute Cholecystitis Severity

What it changes

• Grade I and II — early laparoscopic cholecystectomy where local expertise allows. NICE CG188 recommends surgery within 7 days of symptom onset, during the index admission.
• Grade III — resuscitate and treat organ failure; percutaneous cholecystostomy if not fit for surgery; delayed cholecystectomy once recovered. Some units with appropriate expertise still operate early in selected Grade III patients.
• Charlson Comorbidity Index and ASA are incorporated in TG18 to identify Grade III patients who might still tolerate early surgery.

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20. Tokyo Guidelines 2018 — Acute Cholangitis

Diagnosis requires elements from all three of:

• A. Systemic inflammation — fever/rigors or raised inflammatory markers
• B. Cholestasis — jaundice or abnormal LFTs
• C. Imaging — biliary dilatation or evidence of an aetiology (stone, stricture, stent)

Suspected = one item from A plus one from B or C. Definite = one item from each.

Charcot's triad (RUQ pain, fever, jaundice) is present in only around 50–70%. Reynolds' pentad adds hypotension and confusion — that is Grade III until proven otherwise.

Drainage: ERCP first-line; PTC if ERCP fails or anatomy prevents it; surgical drainage now rare.

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21. Revised Atlanta Classification (2012) — Acute Pancreatitis

Diagnosis — 2 of 3

1. Characteristic abdominal pain
2. Amylase or lipase >3× upper limit of normal
3. Characteristic imaging findings

Severity

Organ failure defined by modified Marshall score ≥2 for respiratory, cardiovascular or renal systems.

Local complications — the terminology matters

Getting this right matters because it dictates intervention: a pseudocyst is drained endoscopically if symptomatic; walled-off necrosis requires a step-up approach (percutaneous or endoscopic drainage first, then minimally invasive necrosectomy only if needed) rather than open necrosectomy.

Phases

• Early (first week) — driven by SIRS and organ failure. Severity determined by organ failure, not by CT findings. CT in the first 72 hours underestimates necrosis — don't scan too early unless the diagnosis is in doubt.
• Late (>1 week) — driven by local complications and persistent organ failure.

Glasgow-Imrie (PANCREAS) and CRP >150 at 48 hours remain the practical UK severity predictors.

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22. Strasberg Classification — Bile Duct Injury

The classification to know if you are operating on gallbladders.

What it changes

• Type A — most common, usually managed by ERCP and stenting ± drainage of collection.
• Types B and C — depend on the volume of liver drained; may need reconstruction or, occasionally, resection.
• Types D and E — do not attempt repair yourself. Control sepsis, drain, image (MRCP + CT), and refer to a specialist HPB centre. Repair by the injuring surgeon is associated with substantially worse outcomes. Reconstruction is usually Roux-en-Y hepaticojejunostomy.

Prevention beats classification: the critical view of safety, and a willingness to perform subtotal cholecystectomy rather than persist with unclear anatomy.

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23. Bismuth-Corlette — Hilar Cholangiocarcinoma (Klatskin Tumour)

Caudate lobe resection is routinely included because the caudate ducts drain directly into the confluence.

Assessment for resectability requires future liver remnant estimation and often portal vein embolisation to hypertrophy the remnant.

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24. Mirizzi Syndrome — Csendes Classification

Extrinsic compression of the common hepatic duct by a stone impacted in Hartmann's pouch or the cystic duct.

Type I may be managed laparoscopically with care (though conversion rates are high). Types II–IV generally need open surgery with biliary reconstruction. Mirizzi is associated with gallbladder cancer in around 5–28% — send the specimen and consider the diagnosis.

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25. Child-Pugh and MELD

Child-Pugh — operative risk in cirrhosis

Child-Pugh C is a contraindication to elective major abdominal surgery.

MELD

Uses bilirubin, INR and creatinine (MELD-Na adds sodium). Used for transplant allocation and increasingly for perioperative risk. MELD >15 predicts significantly increased surgical mortality.

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PART FIVE — HERNIA CLINIC

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26. EHS Classification — Groin Hernia

The European Hernia Society system, designed to be recorded intraoperatively in a grid.

Type:

• L — Lateral (indirect)
• M — Medial (direct)
• F — Femoral

Size (using the index finger or a 1.5 cm jaw of a laparoscopic grasper as the reference):

• 0 — no hernia detectable
• 1 — <1.5 cm (one finger)
• 2 — 1.5–3 cm (two fingers)
• 3 — >3 cm (more than two fingers)

P = primary, R = recurrent.

Recorded as, for example, L2 P — a primary indirect hernia with a 1.5–3 cm defect.

The older Nyhus classification (still quoted)

What matters in clinic

• Femoral hernias — repair even if asymptomatic. High strangulation risk. More common in women, though inguinal hernia remains the commonest hernia in women.
• Asymptomatic or minimally symptomatic inguinal hernia in men — watchful waiting is a legitimate option, though most eventually cross over to surgery.
• Bilateral or recurrent hernias — laparoscopic repair (TEP or TAPP) is favoured.
• Chronic post-herniorrhaphy pain affects around 10% and is the most important thing to consent for. Document it.

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27. EHS Classification — Ventral and Incisional Hernia

Midline (M):

Lateral (L): L1 subcostal, L2 flank, L3 iliac, L4 lumbar.

Width (W): W1 <4 cm; W2 4–10 cm; W3 ≥10 cm.

W3 hernias and those with loss of domain need specialist assessment — component separation, botulinum toxin to the lateral abdominal wall, or preoperative progressive pneumoperitoneum.

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PART SIX — SKIN AND SOFT TISSUE

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28. Melanoma — Breslow Thickness and Excision Margins

Breslow thickness (mm, measured from the granular layer of the epidermis to the deepest tumour cell) is the single most important prognostic factor.

Each T stage is subdivided a (no ulceration) and b (ulceration present). Ulceration upstages and independently worsens prognosis.

Clark levels (I–V, by anatomical layer) are historical and no longer used for staging — mention only if asked.

Sentinel node biopsy

• Offered for Breslow >0.8 mm, or ≤0.8 mm with ulceration.
• Staging, not therapeutic — MSLT-II showed no overall survival benefit from completion lymphadenectomy after a positive SLNB, but it identifies patients for adjuvant immunotherapy or targeted therapy.
• BRAF V600 testing in stage III–IV disease (approximately 50% of cutaneous melanomas) — determines eligibility for dabrafenib/trametinib.

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29. Non-Melanoma Skin Cancer — Risk Stratification

Basal cell carcinoma

Low risk: <20 mm on trunk/extremities, nodular or superficial subtype, primary, immunocompetent patient. High risk: H-zone of the face (periorbital, nose, lips, ears, nasolabial fold), >20 mm, morphoeic/infiltrative/micronodular subtype, recurrent, perineural invasion, immunosuppression.

Margins: 4–5 mm for low-risk lesions. Mohs micrographic surgery for high-risk sites, recurrent lesions, and aggressive subtypes.

Incomplete excision → re-excise. Recurrence rate after incomplete excision is 30–40%, and recurrent BCCs are considerably harder to treat.

Squamous cell carcinoma

High-risk features: >20 mm diameter, >4 mm depth, poorly differentiated, perineural or lymphovascular invasion, ear/lip/temple location, recurrent, immunosuppression (particularly transplant recipients), arising in scar or chronic wound.

Margins: 4 mm low risk; 6 mm or more for high-risk lesions. Consider imaging and MDT for high-risk disease — SCC does metastasise (2–5% overall, higher with risk features).

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PART SEVEN — THYROID AND NECK CLINIC

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30. Thyroid Nodule — U and Thy Classifications

Ultrasound (BTA U classification)

Suspicious features: solid hypoechoic, microcalcification, taller-than-wide shape, irregular or lobulated margins, intranodular vascularity, associated abnormal lymph nodes.

Cytology (RCPath Thy classification)

The key concept

Thy3f requires surgery because cytology cannot distinguish follicular adenoma from follicular carcinoma. The distinction rests entirely on capsular or vascular invasion, which requires examination of the whole capsule on histology — a needle cannot answer it. Roughly 20% of Thy3f lesions turn out malignant.

The US equivalent is the Bethesda system (I–VI); ACR TI-RADS is the US ultrasound scoring system. Know that they exist and map roughly onto Thy/U.

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31. Thyroid Cancer — Surgical Extent

Before any medullary thyroid cancer surgery: test for RET mutation and exclude phaeochromocytoma (MEN2A/2B). An unsuspected phaeochromocytoma under anaesthesia is potentially fatal.

Consent for thyroidectomy must include: recurrent laryngeal nerve injury (voice), external branch of superior laryngeal nerve (pitch), hypoparathyroidism, and haematoma with airway compromise — with clip removers at the bedside.

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PART EIGHT — VASCULAR (WHAT A GENERAL SURGEON STILL SEES)

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32. Fontaine and Rutherford — Peripheral Arterial Disease

Fontaine III–IV = chronic limb-threatening ischaemia (CLTI) → urgent vascular referral for revascularisation.

ABPI: >1.4 falsely elevated (calcification, diabetes); 0.9–1.4 normal; 0.5–0.9 claudication; <0.5 severe; <0.4 critical.

Claudication alone — supervised exercise therapy plus cardiovascular risk factor modification is first-line (NICE). The limb prognosis is good; the cardiovascular prognosis is not.

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33. WIfI Classification — Diabetic and Ischaemic Foot

Three components, each graded 0–3:

• Wound (extent and depth)
• Ischaemia (ABPI, ankle and toe pressures)
• foot Infection (severity)

Produces a stratified estimate of amputation risk at 1 year and likely benefit from revascularisation. More useful than ABPI alone in diabetics with calcified vessels.

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34. CEAP — Chronic Venous Disease

Suffix S (symptomatic) or A (asymptomatic). Full CEAP also records Etiology, Anatomy, Pathophysiology.

C2S and above with confirmed truncal reflux on duplex → refer for intervention. NICE NG168 recommends endovenous thermal ablation first-line, foam sclerotherapy second, surgery third.

C6 (active ulcer) → compression plus early endovenous ablation, which speeds healing and reduces recurrence (EVRA trial).

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QUICK REFERENCE — Clinic Cheat Sheet

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Using This in Clinic

Three habits that make classifications work for you rather than against you:

Give the grade and the consequence in the same breath. "Hinchey II, so I'd want radiological drainage rather than theatre" is a complete answer. "Hinchey II" is a quiz response.

Say which version you're using. TNM 8th or 9th. BSG or ESGE intervals. Original or modified Hinchey. Knowing that versions differ is a stronger position than confidently quoting one.

Record the score in the letter. A Vaizey score, a CEAP class, an EHS grade — these make the next clinic letter meaningful and turn your practice into auditable data. It also makes you the registrar whose letters people actually want to read.

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This reference reflects guidance current as of August 2026. NICE, BSG, ACPGBI, AUGIS, ABS and Vascular Society guidance is periodically revised — verify against current published guidance and local trust protocol before applying to patient care. Educational resource; not a substitute for clinical judgement.