from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, KeepTogether, PageBreak
)
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib import colors
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import cm, mm
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY

OUTPUT = "/tmp/workspace/implant-removal-pdf/Implant_Removal_Orthopaedics.pdf"

# ── Page geometry ──────────────────────────────────────────────────────────────
doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    leftMargin=2.2*cm, rightMargin=2.2*cm,
    topMargin=2.2*cm,  bottomMargin=2.2*cm,
    title="Implant Removal in Orthopaedics",
    author="Orris Medical"
)

W, H = A4

# ── Colour palette ─────────────────────────────────────────────────────────────
C_DARK   = colors.HexColor("#1a2e4a")   # dark navy
C_MID    = colors.HexColor("#2d6a9f")   # medium blue
C_LIGHT  = colors.HexColor("#dce8f5")   # pale blue
C_ACCENT = colors.HexColor("#c0392b")   # red accent
C_GREEN  = colors.HexColor("#1e6b45")   # dark green
C_LGREY  = colors.HexColor("#f4f4f4")   # light grey for alt rows
C_WHITE  = colors.white
C_BLACK  = colors.HexColor("#1a1a1a")

# ── Styles ─────────────────────────────────────────────────────────────────────
base = getSampleStyleSheet()

def ps(name, parent="Normal", **kw):
    return ParagraphStyle(name, parent=base[parent], **kw)

styles = {
    "title": ps("DocTitle", "Title",
                fontSize=22, textColor=C_DARK, spaceAfter=4,
                fontName="Helvetica-Bold", alignment=TA_CENTER),
    "subtitle": ps("DocSub", fontSize=12, textColor=C_MID,
                   spaceAfter=2, alignment=TA_CENTER, fontName="Helvetica"),
    "date": ps("DocDate", fontSize=9, textColor=colors.grey,
               spaceAfter=16, alignment=TA_CENTER, fontName="Helvetica-Oblique"),

    "h1": ps("H1", fontSize=13, textColor=C_WHITE,
             fontName="Helvetica-Bold", spaceBefore=14, spaceAfter=6,
             leftIndent=-4, leading=18),
    "h2": ps("H2", fontSize=11, textColor=C_DARK,
             fontName="Helvetica-Bold", spaceBefore=10, spaceAfter=4,
             borderPad=2),
    "h3": ps("H3", fontSize=10, textColor=C_MID,
             fontName="Helvetica-Bold", spaceBefore=7, spaceAfter=3),

    "body": ps("Body", fontSize=9.5, leading=14, spaceAfter=5,
               textColor=C_BLACK, alignment=TA_JUSTIFY),
    "bullet": ps("Bullet", fontSize=9.5, leading=13, spaceAfter=3,
                 textColor=C_BLACK, leftIndent=14, firstLineIndent=-10),
    "subbullet": ps("SubBullet", fontSize=9, leading=12, spaceAfter=2,
                    textColor=C_BLACK, leftIndent=26, firstLineIndent=-10),
    "caption": ps("Caption", fontSize=8, textColor=colors.grey,
                  alignment=TA_CENTER, fontName="Helvetica-Oblique"),
    "note": ps("Note", fontSize=8.5, textColor=C_GREEN,
               fontName="Helvetica-Oblique", spaceAfter=4),
    "source": ps("Source", fontSize=7.5, textColor=colors.grey,
                 fontName="Helvetica-Oblique", spaceAfter=2),
}

# ── Helper builders ────────────────────────────────────────────────────────────
def section_header(text):
    """Coloured banner for H1 sections."""
    tbl = Table([[Paragraph(text, styles["h1"])]], colWidths=[W - 4.4*cm])
    tbl.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), C_DARK),
        ("TOPPADDING",    (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("LEFTPADDING",   (0,0), (-1,-1), 10),
        ("RIGHTPADDING",  (0,0), (-1,-1), 10),
        ("ROUNDEDCORNERS", [4]),
    ]))
    return tbl

def h2(text):
    return Paragraph(text, styles["h2"])

def h3(text):
    return Paragraph(text, styles["h3"])

def body(text):
    return Paragraph(text, styles["body"])

def bullet(text, sub=False):
    s = styles["subbullet"] if sub else styles["bullet"]
    return Paragraph(f"• {text}", s)

def spacer(h=4):
    return Spacer(1, h*mm)

def hr(color=C_MID, thickness=0.5):
    return HRFlowable(width="100%", thickness=thickness, color=color, spaceAfter=4)

def two_col_table(data, col_widths=None, header=True):
    """Generic styled 2-column table."""
    if col_widths is None:
        col_widths = [(W-4.4*cm)*0.38, (W-4.4*cm)*0.62]
    t = Table(data, colWidths=col_widths, hAlign="LEFT")
    style = [
        ("FONTNAME",  (0,0), (-1,-1), "Helvetica"),
        ("FONTSIZE",  (0,0), (-1,-1), 9),
        ("LEADING",   (0,0), (-1,-1), 13),
        ("VALIGN",    (0,0), (-1,-1), "TOP"),
        ("TOPPADDING",(0,0), (-1,-1), 4),
        ("BOTTOMPADDING",(0,0),(-1,-1),4),
        ("LEFTPADDING",(0,0),(-1,-1),6),
        ("RIGHTPADDING",(0,0),(-1,-1),6),
        ("GRID",      (0,0), (-1,-1), 0.4, colors.HexColor("#c0c0c0")),
        ("ROWBACKGROUNDS",(0,0),(-1,-1),[C_WHITE, C_LGREY]),
    ]
    if header:
        style += [
            ("BACKGROUND", (0,0), (-1,0), C_MID),
            ("TEXTCOLOR",  (0,0), (-1,0), C_WHITE),
            ("FONTNAME",   (0,0), (-1,0), "Helvetica-Bold"),
            ("FONTSIZE",   (0,0), (-1,0), 9),
        ]
    t.setStyle(TableStyle(style))
    return t

def multi_col_table(data, col_widths=None, header=True):
    """Generic styled multi-column table."""
    avail = W - 4.4*cm
    if col_widths is None:
        n = len(data[0])
        col_widths = [avail/n]*n
    t = Table(data, colWidths=col_widths, hAlign="LEFT", repeatRows=1)
    style = [
        ("FONTNAME",  (0,0), (-1,-1), "Helvetica"),
        ("FONTSIZE",  (0,0), (-1,-1), 8.5),
        ("LEADING",   (0,0), (-1,-1), 12),
        ("VALIGN",    (0,0), (-1,-1), "TOP"),
        ("TOPPADDING",(0,0), (-1,-1), 4),
        ("BOTTOMPADDING",(0,0),(-1,-1),3),
        ("LEFTPADDING",(0,0),(-1,-1),5),
        ("RIGHTPADDING",(0,0),(-1,-1),5),
        ("GRID",      (0,0), (-1,-1), 0.4, colors.HexColor("#c0c0c0")),
        ("ROWBACKGROUNDS",(0,1),(-1,-1),[C_WHITE, C_LGREY]),
    ]
    if header:
        style += [
            ("BACKGROUND", (0,0), (-1,0), C_DARK),
            ("TEXTCOLOR",  (0,0), (-1,0), C_WHITE),
            ("FONTNAME",   (0,0), (-1,0), "Helvetica-Bold"),
            ("FONTSIZE",   (0,0), (-1,0), 9),
        ]
    t.setStyle(TableStyle(style))
    return t

def box_note(text, color=C_LIGHT, border=C_MID):
    """Highlighted note box."""
    t = Table([[Paragraph(text, styles["body"])]], colWidths=[W-4.4*cm])
    t.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,-1), color),
        ("BOX",           (0,0), (-1,-1), 1, border),
        ("TOPPADDING",    (0,0), (-1,-1), 6),
        ("BOTTOMPADDING", (0,0), (-1,-1), 6),
        ("LEFTPADDING",   (0,0), (-1,-1), 10),
        ("RIGHTPADDING",  (0,0), (-1,-1), 10),
    ]))
    return t

# ── Cover page ─────────────────────────────────────────────────────────────────
def cover_page():
    elems = []
    elems.append(spacer(30))
    # top banner
    banner = Table(
        [[Paragraph("ORTHOPAEDICS", ps("BannerTop", fontSize=11,
                    textColor=C_LIGHT, fontName="Helvetica-Bold",
                    alignment=TA_CENTER))]],
        colWidths=[W-4.4*cm]
    )
    banner.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), C_DARK),
        ("TOPPADDING",    (0,0), (-1,-1), 10),
        ("BOTTOMPADDING", (0,0), (-1,-1), 10),
    ]))
    elems.append(banner)
    elems.append(spacer(8))
    elems.append(Paragraph("Implant Removal", styles["title"]))
    elems.append(spacer(2))
    elems.append(Paragraph("Long Answer | Comprehensive Review", styles["subtitle"]))
    elems.append(spacer(2))
    elems.append(Paragraph("Campbell's Operative Orthopaedics 15th Ed 2026  •  Rockwood & Green's Fractures in Adults 10th Ed 2025", styles["date"]))
    elems.append(spacer(10))
    elems.append(hr(C_MID, 1.5))
    elems.append(spacer(6))

    # Key facts box
    kf_data = [
        [Paragraph("<b>Key Facts</b>", ps("KFH", fontSize=10, textColor=C_WHITE,
                   fontName="Helvetica-Bold")), ""],
        [Paragraph("Refracture risk (forearm plates)", styles["body"]),
         Paragraph("<b>Up to 18–22%</b>", ps("KFV", fontSize=9.5, textColor=C_ACCENT,
                   fontName="Helvetica-Bold"))],
        [Paragraph("Minimum wait before forearm plate removal", styles["body"]),
         Paragraph("<b>12–18 months</b>", styles["body"])],
        [Paragraph("Post-removal protection", styles["body"]),
         Paragraph("<b>Splint/brace 4–6 weeks</b>", styles["body"])],
        [Paragraph("Screw hole <10% bone diameter", styles["body"]),
         Paragraph("<b>No change in torsional strength</b>", styles["body"])],
        [Paragraph("Screw hole 10–20% bone diameter", styles["body"]),
         Paragraph("<b>34% drop in torsional strength</b>", styles["body"])],
        [Paragraph("Infection / nerve injury rate (forearm removal)", styles["body"]),
         Paragraph("<b>Up to 21%</b>", styles["body"])],
        [Paragraph("Overall complication rate (pooled 871 pts)", styles["body"]),
         Paragraph("<b>~10%</b>", styles["body"])],
    ]
    kf = Table(kf_data, colWidths=[(W-4.4*cm)*0.65, (W-4.4*cm)*0.35])
    kf.setStyle(TableStyle([
        ("BACKGROUND",    (0,0), (-1,0), C_DARK),
        ("TEXTCOLOR",     (0,0), (-1,0), C_WHITE),
        ("SPAN",          (0,0), (-1,0)),
        ("BACKGROUND",    (0,1), (-1,-1), C_LIGHT),
        ("ROWBACKGROUNDS",(0,1),(-1,-1),[C_LIGHT, C_WHITE]),
        ("GRID",          (0,0), (-1,-1), 0.4, C_MID),
        ("TOPPADDING",    (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING",   (0,0), (-1,-1), 8),
        ("RIGHTPADDING",  (0,0), (-1,-1), 8),
        ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ]))
    elems.append(kf)
    elems.append(spacer(8))
    elems.append(hr(C_MID, 0.5))
    # Table of contents outline
    elems.append(spacer(4))
    elems.append(h2("Contents"))
    toc = [
        "1.  Definition",
        "2.  Classification of Implants",
        "3.  Indications (Absolute / Relative / Controversial)",
        "4.  Timing of Removal",
        "5.  Contraindications",
        "6.  Surgical Technique — General Principles",
        "7.  Specific Techniques (Plate, IMN, K-Wire, Prosthesis)",
        "8.  Complications (Refracture, Nerve Injury, Infection…)",
        "9.  Considerations by Anatomical Region",
        "10. Special Situations",
        "11. Post-operative Care",
        "12. Economic Considerations & Current Evidence",
        "13. Summary",
    ]
    for t in toc:
        elems.append(bullet(t))
    elems.append(PageBreak())
    return elems

# ── Content ────────────────────────────────────────────────────────────────────
def build_content():
    E = []

    # ── 1. Definition ──────────────────────────────────────────────────────────
    E.append(section_header("1.  Definition"))
    E.append(spacer(3))
    E.append(body(
        "Implant removal refers to the surgical extraction of metallic or non-metallic "
        "fixation devices — plates, screws, intramedullary nails, wires, external fixator "
        "pins, or prosthetic components — that were previously implanted for fracture "
        "fixation, joint reconstruction, or deformity correction, following completion "
        "of their mechanical or biological role."
    ))
    E.append(spacer(4))

    # ── 2. Classification ──────────────────────────────────────────────────────
    E.append(section_header("2.  Classification of Implants Removed"))
    E.append(spacer(3))
    cls_data = [
        ["Category", "Examples"],
        ["Internal fixation", "Plates & screws (cortical, locking, cancellous),\nintramedullary nails, dynamic hip screws,\nK-wires, cerclage wires"],
        ["External fixation", "Schanz pins, ring fixator wires"],
        ["Joint prostheses", "Total knee, hip, ankle arthroplasty components"],
        ["Syndesmotic fixation", "Syndesmotic screws, suture buttons"],
        ["Tension band", "Tension band wire (patella, olecranon)"],
    ]
    E.append(multi_col_table(cls_data, col_widths=[(W-4.4*cm)*0.32, (W-4.4*cm)*0.68]))
    E.append(spacer(6))

    # ── 3. Indications ─────────────────────────────────────────────────────────
    E.append(section_header("3.  Indications for Implant Removal"))
    E.append(spacer(3))
    E.append(box_note(
        "Indications fall into three broad categories: "
        "<b>Absolute (Mandatory)</b>, <b>Relative</b>, and "
        "<b>Controversial / Prophylactic</b>."
    ))
    E.append(spacer(4))

    # 3a Absolute
    E.append(h2("3a.  Absolute (Mandatory) Indications"))

    E.append(h3("i.  Infection / Sepsis around the Implant"))
    E.append(body(
        "Deep infection around metallic hardware is a major absolute indication. "
        "Biofilm formation on implant surfaces makes eradication impossible without "
        "removal. For acute infections where bone union has NOT yet occurred, "
        "irrigation and debridement with implant retention may be attempted. "
        "Once union is confirmed, the implant must be removed. For intramedullary "
        "nail infections: nail removal, reaming, and placement of an antibiotic-impregnated "
        "cement rod are performed to eradicate infection "
        "<i>(Rockwood &amp; Green's, p. 2860).</i>"
    ))

    E.append(h3("ii.  Broken / Failed Implant"))
    E.append(body(
        "A broken plate or nail indicates implant fatigue, usually at the non-union "
        "site, transitional zones, or interlocking screw holes. Broken IMN removal "
        "techniques include: extraction bolt / conical bolt; long hook method; "
        "guidewire stacking (interference fit); small cortical window approach "
        "from the far end <i>(Rockwood &amp; Green's, p. 2860).</i>"
    ))

    E.append(h3("iii.  Implant Migration"))
    E.append(body(
        "Migrating K-wires (from shoulder, wrist, hip) can penetrate vital structures "
        "(lung, vessels, spinal canal) and must be removed urgently."
    ))

    E.append(h3("iv.  Implant Prominence / Soft Tissue Irritation"))
    E.append(body(
        "Prominent hardware causes persistent skin irritation, bursitis, or wound "
        "breakdown. Subcutaneous hardware (ulnar plate, clavicle plate, K-wires "
        "at the elbow) is particularly symptomatic because of minimal muscle coverage. "
        "Ulnar plates are at highest risk — they should be placed on the dorsal or volar "
        "surface to allow muscle coverage <i>(Rockwood &amp; Green's, p. 415).</i>"
    ))

    E.append(h3("v.  Malposition / Loss of Reduction"))
    E.append(body(
        "Misplaced screws penetrating articular cartilage (ankle, knee, hip); "
        "hardware impinging on tendons or nerves."
    ))

    E.append(h3("vi.  Growth Disturbance (Pediatric)"))
    E.append(body(
        "Implants crossing physeal plates can cause premature physeal arrest and "
        "angular deformity. Must be removed before significant growth disturbance occurs."
    ))

    E.append(h3("vii.  Sinus Tract"))
    E.append(body(
        "A sinus tract with purulent discharge implies implant involvement — absolute "
        "indication for removal."
    ))

    E.append(spacer(4))
    E.append(h2("3b.  Relative Indications"))
    rel = [
        ("<b>Persistent pain</b>", "Deep pain at surgical site, especially in cold weather; removal only after weighing risks"),
        ("<b>Symptomatic retained hardware</b>", "Discomfort, restricted movement, palpable/visible hardware — most common reason for elective removal"),
        ("<b>Planned future surgery</b>", "Hardware removal before arthroplasty, osteotomy, or revision surgery in same region"),
        ("<b>Non-union with implant in situ</b>", "Implant removal + re-fixation with bone grafting"),
        ("<b>Syndesmotic screw removal</b>", "At 8–12 weeks to restore syndesmotic motion before weight-bearing"),
    ]
    rel_data = [["Indication", "Details"]] + [[Paragraph(a, styles["body"]), Paragraph(b, styles["body"])] for a,b in rel]
    E.append(multi_col_table(rel_data, col_widths=[(W-4.4*cm)*0.35, (W-4.4*cm)*0.65]))

    E.append(spacer(4))
    E.append(h2("3c.  Controversial / Prophylactic Indications"))
    E.append(body(
        "Routine removal in children <b>under 16 years</b> is advocated by ~60% of surgeons. "
        "Routine removal in adults aged 16–35: supported by only ~12% of surgeons. "
        "Routine removal in patients over 35: only ~3% of surgeons advocate this. "
        "Cosmetically disturbing hardware in subcutaneous locations is another consideration."
    ))
    E.append(spacer(6))

    # ── 4. Timing ──────────────────────────────────────────────────────────────
    E.append(section_header("4.  Timing of Implant Removal"))
    E.append(spacer(3))
    timing_data = [
        ["Implant", "Minimum Waiting Time"],
        ["K-wires (temporary fixation)", "3–6 weeks"],
        ["Plates & screws (forearm, tibia)", "12–18 months minimum"],
        ["Syndesmotic screws", "8–12 weeks"],
        ["IMN (femur/tibia)", "After confirmed union, usually 12–24 months"],
        ["Pediatric implants crossing physis", "Before growth disturbance (4–6 months)"],
        ["Clavicular plate", "12–18 months"],
    ]
    E.append(multi_col_table(timing_data))
    E.append(spacer(4))
    E.append(box_note(
        "<b>Key principle:</b> Hardware removal from the forearm should be delayed by at "
        "least <b>12–18 months</b> to allow adequate remodelling and reduce refracture risk. "
        "Protective external support (splint / brace) for <b>4–6 weeks post-removal</b> is "
        "recommended. Implant removal should only be considered once fracture union is "
        "radiologically confirmed <i>(Rockwood &amp; Green's, p. 415).</i>"
    ))
    E.append(spacer(6))

    # ── 5. Contraindications ───────────────────────────────────────────────────
    E.append(section_header("5.  Contraindications"))
    E.append(spacer(3))
    contra = [
        "Patient medically unfit for surgery",
        "Implant deeply embedded with high risk of neurovascular injury on extraction",
        "Asymptomatic implants in elderly patients (unfavourable risk-benefit ratio)",
        "Unconfirmed fracture union",
        "Active anticoagulation without proper bridging plan",
    ]
    for c in contra:
        E.append(bullet(c))
    E.append(spacer(6))

    # ── 6. Surgical Technique — General ───────────────────────────────────────
    E.append(section_header("6.  Surgical Technique — General Principles"))
    E.append(spacer(3))
    steps = [
        ("<b>Pre-operative planning</b>", "Identify the implant system; have appropriate extraction set (matching screwdrivers, extraction bolts, conical bolts, carbide-tipped drill bits)"),
        ("<b>Imaging</b>", "Fluoroscopy must be available intraoperatively"),
        ("<b>Adequate exposure</b>", "Debride adherent soft tissue and bone overlying the implant-bone interface"),
        ("<b>Screw extraction</b>", "Use the correct driver; use a cannulated drill to clear bone overgrowth from screw heads; for stripped screw heads — trephine, screw extractor, reverse torque device, or carbide burr"),
        ("<b>Cold welding</b>", "Titanium screws in titanium plates are prone to cold welding; use anti-seize agent during insertion at index surgery to prevent this"),
        ("<b>Broken screw</b>", "Hollow mill drill over screw, then reverse-torque extractor; leave if asymptomatic and deeply buried"),
    ]
    steps_data = [["Step", "Details"]] + [[Paragraph(a, styles["body"]), Paragraph(b, styles["body"])] for a,b in steps]
    E.append(multi_col_table(steps_data, col_widths=[(W-4.4*cm)*0.28, (W-4.4*cm)*0.72]))
    E.append(spacer(6))

    # ── 7. Specific Techniques ─────────────────────────────────────────────────
    E.append(section_header("7.  Specific Techniques"))
    E.append(spacer(3))

    E.append(h2("7a.  Plate & Screws Removal"))
    E.append(body("Standard approach over previous incision. Remove screws before the plate. "
                  "If screws are stripped: carbide-tipped drill to remove head, or trephine "
                  "around the screw and leave the shaft if not prominent."))

    E.append(h2("7b.  Intramedullary Nail Removal"))
    imn = [
        "Access the nail at the insertion site (antegrade/retrograde)",
        "Remove end cap; insert guidewire",
        "Attach extraction bolt / handle to nail; back-slap extractor to disengage nail",
        "<b>Broken nail techniques:</b>",
        "Conical bolt method (reverse-threaded tapered bolt cuts new threads into nail)",
        "Hook technique: long hook down cannulated portion to catch the nail end",
        "Cortical window: small cortical window at far end; flexible reamer to knock nail out",
        "Guidewire stacking: multiple guidewires for interference fit; pull with bead-tip wire",
    ]
    for i in imn:
        E.append(bullet(i, sub=i.startswith("Conical") or i.startswith("Hook") or i.startswith("Cortical") or i.startswith("Guidewire")))

    E.append(h2("7c.  K-Wire Removal"))
    E.append(body("Usually done in OPD under local anaesthesia. Cut wire flush with skin if buried; "
                  "use wire-pulling pliers."))

    E.append(h2("7d.  Prosthesis / Arthroplasty Removal (Revision)"))
    E.append(body(
        "More complex — requires full exposure. Debride bone-implant interface with fine "
        "chisels and osteotomes. For total ankle arthroplasty: disengage polyethylene liner "
        "first (know the locking mechanism), then remove tibial and talar components with "
        "chisels; take care to avoid malleolar fracture — consider prophylactic K-wires for "
        "susceptible malleoli <i>(Campbell's Operative Orthopaedics, p. 3752–3768).</i>"
    ))
    E.append(spacer(6))

    # ── 8. Complications ───────────────────────────────────────────────────────
    E.append(section_header("8.  Complications of Implant Removal"))
    E.append(spacer(3))

    E.append(h2("8a.  Refracture (Most Important Complication)"))
    E.append(box_note(
        "Overall refracture rate: <b>up to 18–22%</b> for forearm plates. "
        "Early series with 4.5-mm plates reported up to 22%; later series with "
        "3.5-mm compression plates showed lower rates.",
        color=colors.HexColor("#fdf2f2"), border=C_ACCENT
    ))
    E.append(spacer(3))

    E.append(h3("Mechanisms"))
    E.append(bullet("<b>Stress riser effect</b> of empty screw holes — holes act as stress concentration points"))
    E.append(bullet("<b>Stress shielding</b> — cortex becomes osteoporotic under the plate during fixation period"))

    E.append(h3("Biomechanical Data (Rockwood & Green's, p. 424–428)"))
    bio_data = [
        ["Defect Size (% of bone diameter)", "Effect on Torsional Strength"],
        ["< 10%", "No change"],
        ["10% → 20%", "34% DROP"],
        ["> 20%", "Linear further decrease"],
        ["Unicortical defect", "22% reduction"],
        ["Bicortical defect", "26% reduction"],
        ["Distal tibia 3–5 mm defect", "28–38% reduction"],
    ]
    E.append(multi_col_table(bio_data))
    E.append(spacer(4))

    E.append(h3("Prevention of Refracture"))
    prev = [
        "Delay removal by 12–18 months",
        "Protective splint/brace for 4–6 weeks after removal",
        "Avoid torsional activities and contact sports for 3–6 months",
        "Radiological confirmation of union before removal",
        "Prefer 3.5-mm compression plates over 4.5-mm screws in the forearm",
    ]
    for p in prev:
        E.append(bullet(p))

    E.append(spacer(4))
    E.append(h2("8b.  Other Complications"))
    comp_data = [
        ["Complication", "Details"],
        ["Infection", "Post-removal wound infection in up to 21% (forearm). Risk ↑ with deep dissection and lengthy surgical time"],
        ["Nerve injury", "Radial nerve (posterior forearm), superficial peroneal nerve, sural nerve. Up to 8–21% of forearm removals"],
        ["Vascular injury", "Rare; relevant near pelvic fixation, iliac vessels"],
        ["Retained hardware", "Most frequent complication in large series; stripped screws, broken drill bits, nail fragments — leave if asymptomatic"],
        ["Hematoma / wound complications", "Wound dehiscence, seroma"],
        ["Peri-implant fracture (intraoperative)", "Especially during forceful extraction of well-ingrown implant; malleolar fracture during ankle arthroplasty revision"],
        ["Prolonged disability", "Hospital stay 3–168 hours; average work absence ~3.4 weeks (Rockwood & Green's, p. 431)"],
        ["Anaesthetic risk", "General or regional anaesthesia complications"],
    ]
    E.append(multi_col_table(comp_data, col_widths=[(W-4.4*cm)*0.30, (W-4.4*cm)*0.70]))
    E.append(spacer(6))

    # ── 9. Regional ────────────────────────────────────────────────────────────
    E.append(section_header("9.  Considerations by Anatomical Region"))
    E.append(spacer(3))
    reg_data = [
        ["Region", "Key Considerations"],
        ["Forearm (radius/ulna)", "Refracture risk highest (18–22%); subcutaneous ulnar plate symptomatic; 3.5-mm plates safer than 4.5-mm"],
        ["Tibia", "Prominent proximal tibial hardware; IMN after union routinely left unless symptomatic"],
        ["Femur", "IMN: removal only if symptomatic; DHS removal after confirmed union"],
        ["Ankle", "Syndesmotic screw removal at 8–12 weeks; risk of fibula fracture if removed too early"],
        ["Clavicle", "Highly symptomatic subcutaneous plate; high refracture risk if removed before 18 months"],
        ["Children", "Routine removal; crossing-physeal implants must be removed promptly; K-wires at 3–6 weeks"],
    ]
    E.append(multi_col_table(reg_data, col_widths=[(W-4.4*cm)*0.22, (W-4.4*cm)*0.78]))
    E.append(spacer(6))

    # ── 10. Special Situations ─────────────────────────────────────────────────
    E.append(section_header("10.  Implant Removal in Special Situations"))
    E.append(spacer(3))

    E.append(h2("Infection-Related Removal"))
    E.append(body(
        "For periprosthetic joint infection: one-stage or two-stage revision. "
        "For fracture-fixation infection: removal + antibiotic cement spacer + "
        "re-fixation after infection control. Biofilm necessitates hardware removal "
        "as antibiotics alone cannot penetrate biofilm."
    ))

    E.append(h2("Broken Intramedullary Nail"))
    E.append(body(
        "Most common sites of failure: non-union site, transitional zones, interlocking holes. "
        "Franklin et al. identified these in a study of 60 broken nails. Filling interlocking holes "
        "with screws may reduce stress concentration. Multiple extraction techniques are available "
        "(see Section 7b above)."
    ))

    E.append(h2("Pediatric Considerations"))
    E.append(body(
        "~60% of surgeons recommend routine removal in children under 16. "
        "Implants crossing the physis: mandatory removal. K-wires: 3–6 weeks; "
        "flexible IMN: 6–12 months after union. Growth implications, remodelling "
        "potential, and risk of growth arrest must guide timing."
    ))
    E.append(spacer(6))

    # ── 11. Post-op ────────────────────────────────────────────────────────────
    E.append(section_header("11.  Post-operative Care After Implant Removal"))
    E.append(spacer(3))
    postop = [
        "Protective splinting / bracing for 4–6 weeks (especially forearm, tibia)",
        "Gradual return to weight-bearing and activity",
        "Avoid contact sports and torsional activities for 3–6 months",
        "Radiological follow-up at 6 weeks to assess for refracture",
        "Wound care and monitoring for infection",
    ]
    for p in postop:
        E.append(bullet(p))
    E.append(spacer(6))

    # ── 12. Evidence ───────────────────────────────────────────────────────────
    E.append(section_header("12.  Economic Considerations & Current Evidence"))
    E.append(spacer(3))
    E.append(body(
        "Implant removal carries a significant economic burden: revision surgeries, "
        "prolonged hospitalisation, and work absenteeism. This is particularly significant "
        "in low-income countries. Only <b>7% of hospital units</b> have a formal guideline "
        "on implant removal, highlighting widespread variation in practice."
    ))
    E.append(spacer(4))
    evid_data = [
        ["Source", "Key Finding"],
        ["JAAOS 2022 (871 patients, 10 case series)", "10% overall complication rate; complications: fracture, infection, hematoma, wound dehiscence, retained hardware"],
        ["International Orthopaedics 2025", "Implant removal is 'far more than a resident's simple task' — requires thorough pre-operative planning and experienced surgical handling"],
        ["Vos et al., Eur J Trauma 2013", "Routine removal in <16 yr: 60% of surgeons; 16–35 yr: 12%; >35 yr: only 3%"],
        ["Rockwood & Green's 10th ed.", "Refracture rates up to 18–22%; hospital stay 3–168 h; work absence avg. 3.4 weeks"],
    ]
    E.append(multi_col_table(evid_data, col_widths=[(W-4.4*cm)*0.38, (W-4.4*cm)*0.62]))
    E.append(spacer(6))

    # ── 13. Summary ────────────────────────────────────────────────────────────
    E.append(section_header("13.  Summary"))
    E.append(spacer(3))
    E.append(box_note(
        "<b>Implant removal is a common but potentially complex orthopaedic procedure.</b> "
        "The decision to remove hardware must carefully weigh: the nature and severity of "
        "the indication (absolute vs. relative); the timing (adequate fracture union, "
        "minimum 12–18 months for forearm plates); the risks (particularly <b>refracture</b>, "
        "nerve injury, and infection); and the patient's age, activity level, and overall health. "
        "<br/><br/>"
        "Routine removal without a clear indication is <b>not recommended</b> in adults over 35. "
        "In children, removal is often indicated to prevent growth disturbance. "
        "When removal is planned, proper pre-operative preparation with correct instrumentation "
        "is mandatory, and post-removal protection is essential to prevent refracture."
    ))
    E.append(spacer(6))
    E.append(hr(C_MID))
    E.append(spacer(3))
    E.append(Paragraph(
        "Sources: Rockwood and Green's Fractures in Adults, 10th ed. 2025 | "
        "Campbell's Operative Orthopaedics, 15th ed. 2026 | JAAOS Global 2022 | "
        "International Orthopaedics 2025",
        styles["source"]
    ))
    E.append(Paragraph("Generated by Orris Medical AI · July 2026", styles["source"]))

    return E

# ── Build ──────────────────────────────────────────────────────────────────────
def on_page(canvas, doc):
    canvas.saveState()
    # footer
    canvas.setFont("Helvetica", 7.5)
    canvas.setFillColor(colors.grey)
    canvas.drawString(2.2*cm, 1.2*cm, "Implant Removal in Orthopaedics — Comprehensive Review")
    canvas.drawRightString(W - 2.2*cm, 1.2*cm, f"Page {doc.page}")
    # top line
    canvas.setStrokeColor(C_MID)
    canvas.setLineWidth(0.5)
    canvas.line(2.2*cm, H - 1.8*cm, W - 2.2*cm, H - 1.8*cm)
    canvas.restoreState()

all_elements = cover_page() + build_content()
doc.build(all_elements, onFirstPage=on_page, onLaterPages=on_page)
print("PDF created:", OUTPUT)