Williamson v Wang: When a Broken Needle Doesn’t Prove a Breach

When a routine medical procedure ends in an obvious adverse outcome — a fractured needle, retained surgical foreign body, unexpected bleed, intraoperative injury — the instinct is to assume that something must have gone wrong with the technique. The outcome was bad; bad outcomes mean substandard care; the standard must have been breached. The doctrinal name for this reasoning pattern is post hoc ergo propter hoc, and it has been firmly rejected in Canadian medical malpractice jurisprudence. The standard of care is assessed against accepted technique, not against the outcome. Many procedures inherently carry the risk of adverse outcomes that do not reflect substandard practice — risks that have been disclosed during the consent process precisely because they exist as accepted possibilities even with competent technique.

Williamson v Wang, 2024 BCSC 1227, is a clean illustration of the principle. The Supreme Court of British Columbia dismissed a medical malpractice claim against an anaesthesiologist who had attempted to administer an obstetric epidural during labour. The attempt was unsuccessful. The epidural needle broke during one of the attempts. A retained fragment had to be surgically removed. The patient subsequently reported chronic back pain and sued, alleging that the needle breakage and the back pain were caused by excessive force during the procedure.

The trial judge dismissed the action on two grounds. First, the standard of care was not breached: the number of attempts, the number of redirections, the time spent on the procedure, and the technique itself were all consistent with what would be expected of a reasonably competent anaesthesiologist performing an obstetric epidural in the circumstances. Second, causation was not established in any event: epidural insertion inherently involves the needle piercing ligamentous tissue, and the plaintiff could not distinguish pain caused by accepted procedural technique from pain allegedly caused by substandard technique.

The case is doctrinally significant in several respects. It introduces anaesthesia and pain medicine as a substantive area in the rewritten case-comment cluster on this site. It articulates a clean rejection of outcome-based reasoning in procedure-based complications. It engages the iatrogenic-pain vs negligent-injury distinction that operates in many procedure-based causation analyses. And it adds another BC case to the cross-province cluster, which is now the most diverse subset of the library.

The clinical context: obstetric epidural anaesthesia

Obstetric epidural anaesthesia is one of the most commonly performed regional anaesthesia procedures in Canadian hospitals. It provides effective pain relief during labour and is widely used for both vaginal delivery and the conversion to cesarean section anaesthesia where required. The procedure is technically demanding but routine within the practice of obstetric anaesthesia.

The technique involves the following sequence:

• The patient is positioned, typically sitting at the edge of the bed with the back curved, or in a lateral decubitus position with knees drawn up
• The lumbar region is prepared with antiseptic and draped
• Local anaesthetic is infiltrated into the skin and subcutaneous tissue at the planned insertion site
• A specialized Tuohy needle (an epidural needle with a curved bevel) is advanced through the skin and underlying tissues
• The needle passes through, in order:
  • Subcutaneous fat
  • Supraspinous ligament
  • Interspinous ligament
  • Ligamentum flavum
• As the tip approaches the ligamentum flavum, the anaesthesiologist applies continuous pressure to a syringe attached to the needle hub, watching for a sudden loss of resistance that signals entry into the epidural space
• A fine catheter is threaded through the needle into the epidural space
• The needle is withdrawn, leaving the catheter in place
• The catheter is secured and connected to a continuous infusion of local anaesthetic and (often) opioid

The procedure is performed entirely by feel and by interpretation of subtle tactile cues. The anaesthesiologist cannot directly visualize the path of the needle through the tissues. Multiple repositioning of the needle is common. When the initial insertion encounters bone (typically a spinous process or vertebral lamina), the anaesthesiologist withdraws the needle partially and redirects — anteriorly, posteriorly, cephalad, or caudad — to find the correct path between the bony structures and through the ligamentous tissues to the epidural space.

Multiple redirections are not failures of technique. They are part of the technique. Anatomical variation, patient positioning, ligamentous calcification, pregnancy-related lumbar lordosis changes, and obesity all make the path through the tissues less predictable. The literature recognizes that the procedure may require multiple attempts even in skilled hands, particularly in technically difficult patients.

Complications of obstetric epidural anaesthesia include:

• Dural puncture (penetration of the dura mater beyond the epidural space), with subsequent post-dural-puncture headache
• Failed epidural (no analgesic effect from the placed catheter)
• Patchy or unilateral block (incomplete or asymmetric anaesthetic distribution)
• Transient neurological symptoms (temporary nerve irritation)
• Persistent nerve injury (rare)
• Epidural haematoma (rare; more common with anticoagulation)
• Epidural abscess (rare)
• Catheter breakage and retention
• Needle breakage and retention — the issue in Williamson

Needle breakage during epidural attempts is uncommon but recognized. It can result from excessive bending of the needle (typically against bone), material defects in the needle, patient movement during the procedure, anatomical features that produce unexpected impingement, or the cumulative stress of multiple insertion attempts. Where a needle fragment is retained, surgical removal is typically required. The procedure is usually straightforward when the fragment is identified promptly and is in an accessible location.

The substantive facts

The patient was pregnant with her first child and in labour. She requested an epidural for pain management. Dr. Jing Jang Wang, an anaesthesiologist, attempted to place the epidural.

The attempt did not proceed smoothly. The needle required multiple redirections through the patient’s back as Dr. Wang attempted to find the correct path through the ligamentous tissues to the epidural space. During one of the attempts, the epidural needle fractured. A portion of the needle was retained in the patient’s back.

Dr. Wang did not attempt to continue the procedure. She located the retained needle fragment and surgically excised it shortly after the breakage. The plaintiff later conceded at trial that this excision was entirely successful — the fragment was completely removed, no infection followed, and the question of who should have performed the excision was no longer relevant to the case.

The plaintiff alleged that she developed chronic back pain after the failed epidural attempt and that the pain has continued. She brought the action against Dr. Wang alleging that the needle fracture and her ongoing back pain were caused by Dr. Wang’s use of excessive force during the multiple redirections.

The competing expert evidence

Plaintiff’s expert: Dr. Darren Ezer (anaesthesiologist). Dr. Ezer opined that:

• Dr. Wang used excessive force during the epidural attempt
• The multiple redirections caused tissue damage
• The excessive force fell below the standard of care for an anaesthesiologist
• Dr. Wang was outside the normal scope of practice for an anaesthesiologist in performing the surgical excision herself

The latter point — about the excision being outside scope — became immaterial when the plaintiff conceded at trial that the excision was entirely successful and nothing turned on who performed it. The substantive part of Dr. Ezer’s evidence was the excessive force opinion.

Defendant’s expert: Dr. Steven Head (anaesthesiologist). Dr. Head opined that:

• The standard of care was met by Dr. Wang
• The number of attempts and redirections was within the range of accepted technique
• The technique itself was not improper
• Needle breakage during epidural attempts is a recognized complication that does not by itself indicate substandard practice

The court was therefore presented with two qualified anaesthesiology experts offering directly opposing views on the standard of care. This is the typical structure of malpractice expert evidence — the trier of fact must choose between the competing opinions, or accept neither, based on the persuasiveness of the analysis and the foundations on which the opinions rest.

The trial outcome: standard of care

The trial judge accepted Dr. Head’s analysis and rejected Dr. Ezer’s. The findings included:

Number of attempts. The number of insertion attempts and redirections by Dr. Wang was not inconsistent with the standard of care expected of an anaesthesiologist attempting an obstetric epidural. Multiple attempts are common in challenging cases. There was no specific number above which the standard would be breached.

Time spent. The duration of the attempted procedure was not inconsistent with the standard of care. Difficult epidurals can take substantial time even with proper technique.

Technique. The technique used by Dr. Wang was not improper. The plaintiff did not demonstrate any specific aspect of the technique that fell below accepted practice.

The needle breakage. The needle breakage itself was not evidence of substandard technique. Needles can break in the course of accepted technique for reasons that do not reflect on the practitioner’s skill. The plaintiff’s effort to use the breakage as retrospective evidence of excessive force was rejected.

The plaintiff therefore failed to prove that Dr. Wang’s actions fell below the standard of care for an anaesthesiologist performing an obstetric epidural in the circumstances.

The alternative causation finding

The trial judge also addressed causation in the alternative — that is, on the assumption that the SOC analysis had gone differently and a breach had been established. Even on that assumption, the causation analysis would have defeated the claim.

The reasoning is doctrinally important and worth quoting in substance. Successful epidural placement inherently requires the needle to pass through ligamentous tissue. Every epidural — competent or otherwise — involves the needle piercing tissue in the patient’s back. The plaintiff was therefore required to distinguish:

• Tissue trauma inherent to a properly performed epidural (baseline)
• Tissue trauma caused by any departure from proper technique (the alleged breach)
• Causal connection between the breach-related trauma and the chronic pain claimed

The plaintiff could not make this distinction on the evidence. There was no evidence that Dr. Wang’s specific manipulations caused tissue damage materially different from what is expected with accepted technique. There was no evidence that the chronic pain was specifically referable to negligent technique rather than to the inherent procedural trauma. The plaintiff therefore could not establish that the alleged breach (had it occurred) caused the alleged harm.

The rejection of outcome-based reasoning

The doctrinal centerpiece of Williamson v Wang is the clean rejection of outcome-based reasoning. The plaintiff’s case relied heavily on the inference that the needle breakage itself proved excessive force. The trial judge refused to draw that inference.

The principle: the standard of care is measured against accepted technique, not against outcome. Many procedures inherently carry risks of adverse outcomes that do not reflect substandard practice. Needles can break with competent technique. Patients can develop complications without negligence. Outcomes that turn out badly do not, by their badness alone, prove that the underlying care fell below the standard.

The principle has been articulated in many Canadian cases. Wilson v Swanson, [1956] SCR 804, is the foundational authority — mere error of judgment is not negligence. ter Neuzen v Korn, [1995] 3 SCR 674, applies the principle in the context of accepted medical practice. The principle operates against both retrospective evaluation by hindsight and post hoc inference from outcome.

This is the same principle that has appeared in several other cases in the rewritten cluster:

• Focken v Miller (BC CA): the “judicial humility” doctrine — courts should not second-guess clinical decisions made within the range of reasonable practice based on outcomes that turned out badly
• Rybakov v Khattak (BC CA): the expert evidence requirement — adverse outcomes alone do not establish breach without qualified expert evidence on the standard
• Papineau v Romero-Sierra (Ontario): the Wilson v Swanson judgment-call doctrine — reasonable clinical judgments are not breaches even if other physicians would have done differently

Williamson v Wang fits within this established framework. The outcome-based inference offered by the plaintiff was not accepted because the standard is measured against technique, not against result.

The Anderson v Chasney exception (implicit)

A natural argument in needle breakage cases is that the doctrine of res ipsa loquitur (“the thing speaks for itself”) should apply. The plaintiff’s implicit argument is: needles don’t break absent negligence; therefore the breakage itself proves the breach. The Canadian approach to this kind of inference is the Anderson v Chasney, [1949] 4 DLR 71 (SCC), exception — the inference can be drawn only where the breach is “plainly obvious” without the need for expert evidence.

The exception is narrow. It applies where the alleged negligence is something a layperson would recognize as below standard without medical expertise — retained surgical sponges, operating on the wrong limb, leaving instruments in the body cavity. It does not generally apply to needle breakage during accepted procedures where the breakage can occur with competent technique and where expert evidence is required to assess whether the technique was below standard.

Williamson v Wang falls outside the Anderson v Chasney exception. Needle breakage during epidural attempts is not within the narrow category of “plainly obvious negligence.” Expert evidence was required to assess whether the technique was below standard. The plaintiff offered such evidence; the court did not accept it as outweighing the defence expert’s contrary view. The framework operated correctly: expert evidence resolved the SOC question, and outcome-based inference was not permitted to displace that resolution.

The framework is consistent with the Anderson v Chasney analysis in Rybakov and Focken, both of which engaged the exception explicitly. Williamson engages it implicitly through the requirement of expert evidence and the rejection of pure outcome-based reasoning.

The iatrogenic-pain vs negligent-injury distinction

A second doctrinally important feature of Williamson v Wang is the causation framework that distinguishes pain inherent to a properly performed procedure from pain caused by negligent execution of the procedure.

Many procedures inherently involve some degree of tissue trauma. Epidural insertion requires needle passage through skin, subcutaneous tissue, supraspinous ligament, interspinous ligament, and ligamentum flavum. Surgery involves incision. Catheter placement involves vessel manipulation. Joint injection involves needle passage through soft tissue and capsule. Some procedure-related discomfort is therefore the expected baseline, not the consequence of any breach.

The causation question in procedure-based complication cases is therefore not simply “did the procedure cause the harm?” but the more refined question “did the alleged breach cause harm beyond what would have occurred with proper technique?”

The framework requires the plaintiff to:

• Identify the proper technique (the baseline)
• Identify how the actual technique deviated from the proper technique (the alleged breach)
• Show that the deviation caused harm beyond what would have occurred at the baseline
• Quantify or characterize the additional harm with sufficient specificity to support damages

The plaintiff in Williamson could not complete this analytical sequence. The chronic back pain might have been caused by the inherent tissue trauma of the epidural attempt (baseline, not actionable); it might have been caused by something specific to Dr. Wang’s technique (alleged breach, actionable if proven). The plaintiff’s evidence did not distinguish between the two possibilities. Causation therefore failed.

The framework has practical implications well beyond anaesthesia. Any procedure-based complication case must confront this distinction. The plaintiff must articulate, with evidentiary support, what the proper technique would have produced and how the alleged breach produced additional harm beyond that baseline. Where the evidence cannot make this distinction, causation will fail.

The doctrinal lessons

The case stands for several propositions.

Outcome alone does not prove breach. Adverse outcomes during routine procedures do not, by their badness alone, establish breach of the standard of care. The standard is measured against accepted technique, not against result. Where competent technique can produce the same outcome, the outcome alone provides no evidence of breach.

Expert evidence is required for technical SOC questions. Outside the narrow Anderson v Chasney exception, expert evidence is necessary to establish that a procedural technique fell below standard. Lay inference from the fact of an adverse outcome is insufficient.

Multiple redirections during an epidural are not failures of technique. The literature recognizes that multiple needle redirections are part of accepted technique for epidural insertion. Anatomical variation and patient factors make the path through the tissues unpredictable. The number of attempts is not, by itself, evidence of substandard practice.

The iatrogenic-pain vs negligent-injury distinction operates in causation. Where a procedure inherently involves tissue trauma, the causation analysis requires the plaintiff to distinguish pain caused by accepted procedural trauma from pain caused by any alleged breach. Failure to make this distinction defeats causation.

Two competent experts opposing each other produces a credibility/persuasiveness contest. Where both sides offer qualified specialists with directly opposing views, the trier of fact must choose between them based on the persuasiveness of the analysis, the foundations of the opinions, and the consistency of the evidence with established practice. There is no presumption favouring either party.

Multi-ground dismissals are durable. Trial judgments that address both SOC and causation produce more appeal-resistant outcomes than judgments resting on a single ground. Williamson v Wang would be difficult to overturn on appeal precisely because the trial judge found both that the SOC was not breached and that causation would have failed even on the assumption of breach.

Cluster integration

Causation/SOC defeat cluster (now 16 cases — comprehensive):

• Williamson, Rybakov, Focken, Papineau, Sutherland, Bendah, Hanson-Tasker, Coville, Knight, Johnson, Martindale, Beazley, Willick, Tripp, A.G. v Rivera, and others

Cross-province cluster (now 15 cases, BC at 9 — most extensive single-province sub-cluster):

• BC: Massie, Sheoran, Gilmore, Lal, Hanson-Tasker, A.G. v Rivera, Rybakov, Focken, Williamson
• Alberta: Khaleel
• Manitoba: Tripp, Dumesnil
• Newfoundland: Quinlan (via 2023 SRL)
• New Brunswick: Scott
• Nova Scotia: Thorburn

New substantive practice area: anaesthesia / pain medicine. First case in the cluster engaging anaesthesia. Extends the doctrinal coverage to a major practice area not previously represented.

Expert evidence cluster context. Williamson fits alongside the cluster’s other expert-evidence cases as a competent-experts-opposing-each-other resolution. Compare with:

• Beazley v Johnston (Ontario): expert qualification failure under White Burgess
• Hanson-Tasker v Ewart (BC): competing experts on causation, Snell discretion
• Knight v Manolakos (Ontario): qualified experts, causation defeat
• Tripp v Ross (Manitoba): competing oncology experts on causation
• Sutherland v Booth (Ontario): cross-examination unraveling of plaintiff’s expert

Anderson v Chasney exception cluster context. Williamson engages the framework implicitly. Compare with:

• Rybakov v Khattak (BC CA): explicit engagement; ECT context
• Focken v Miller (BC CA): explicit engagement; embolization timing
• Williamson v Wang (BC): implicit engagement; equipment breakage

Why this case matters

For prospective clients considering procedure-based complication claims. The case illustrates the structural challenge in these claims. Procedure-based complications may or may not reflect substandard practice. Where competent technique can produce the same outcome, the outcome alone provides no evidence of breach. Successful claims typically require:

• Expert evidence identifying a specific technical departure from accepted practice
• A causal analysis distinguishing the harm from accepted procedural baseline
• Documentation of the deviation that goes beyond the fact of the bad outcome

Cases that rest on the inference “something must have gone wrong because something bad happened” face substantial structural difficulties. For more on the realistic evaluation of malpractice claims, see Suing for Medical Malpractice in Ontario: What You Need to Know and Six Common Misunderstandings About Medical Malpractice.

For plaintiff counsel. The case provides several important reminders:

• Outcome-based inference will not displace expert evidence on technique
• Multiple procedural attempts are not, by themselves, evidence of breach
• Causation requires distinguishing iatrogenic pain (inherent to procedure) from negligent injury (consequence of breach)
• Equipment failure (needle breakage, catheter breakage) does not fit the Anderson v Chasney “plainly obvious negligence” exception
• Multi-ground defence dismissals are particularly difficult to overturn

For defence counsel. The case is a useful precedent on:

• The rejection of outcome-based reasoning in procedure-based complications
• The iatrogenic-pain vs negligent-injury distinction in causation
• Multi-ground analysis as a durable defence strategy
• The framework for resolving competing qualified-expert opinions

For practising anaesthesiologists and other procedure-based specialists. The case offers a measured affirmation of accepted technique. Where the procedure proceeds within accepted parameters — appropriate number of attempts, accepted redirections, proper technique — adverse outcomes that nonetheless occur do not establish negligence. Documentation of the technique used, the parameters within which the procedure proceeded, and the basis for clinical decisions made during the procedure remains essential. Where complications occur, contemporaneous documentation of the recognition and response is similarly important.

For more on Canadian cross-province malpractice jurisprudence, see the other BC cases linked in the cross-province cluster section above. For more on the expert evidence framework, see Beazley v Johnston and related cases.

---

Decision Date: July 9, 2024

Jurisdiction: Supreme Court of British Columbia

Citation: Williamson v Wang, 2024 BCSC 1227 (CanLII)

Outcome: Action dismissed on both standard of care (not breached) and causation (alternative finding of no causation in any event).

Key authorities: Wilson v Swanson, [1956] SCR 804 (error of judgment doctrine, foundational); Crits v Sylvester, [1956] OR 132 (CA), aff’d [1956] SCR 991 (standard of care framework); ter Neuzen v Korn, [1995] 3 SCR 674 (accepted practice and expert evidence); Anderson v Chasney, [1949] 4 DLR 71 (SCC) (plainly obvious negligence exception); Clements v Clements, 2012 SCC 32 (but-for causation framework)