AAOS Bulletin - August, 2006

Medical Liability: The Spine Surgery Perspective

By Bryan A. Fox, MD, and William J. Richardson, MD

Spine surgery has unique risks and complications that set it apart from other orthopaedic subspecialties in the medical liability arena. The lumbar spine ranks as the most common anatomic area involved in orthopaedic medical liability lawsuits and the cervical spine ranks fifth.1 Claims for spine surgery generate the highest indemnity payments and defense costs.

As a result, spine surgeons routinely pay higher malpractice premiums than their “nonspine” orthopaedic colleagues. Little is written in the medical literature about orthopaedic medical liability issues, and even less about issues specific to the spine surgeon. This article is based on a review of the literature and an analysis of claims data associated with common spine disorders from the Physicians Insurers Association of America (PIAA). The PIAA is a trade association of more than 60 medical liability insurance companies that has previously collaborated with the AAOS in a text on managing orthopaedic risks.2

We specifically analyzed 16 ICD-9 codes (insurance claims do not routinely identify CPT codes) for common spine disorders, from 1995 to 2004, to evaluate closed and paid claims with respect to claims disposition, medical misadventure and several other variables. The data in Tables 1 to 3 are based on that analysis.

Overview of claims frequency

Disc pathology—both cervical and lumbar—was the most common diagnosis resulting in lawsuits. This is not surprising because these diagnoses are the most frequently encountered in spine surgery. Because the data show only the numbers of claims filed, without comparative data on incidence of the diagnosis, we could not accurately make any assumption of relative risk. It is always wise to be cautious when attempting to identify relative risk associated with a certain diagnosis. Table 1 shows the number of claims filed, the number of claims paid and the percentage of filed claims that were paid with respect to diagnosis.

Disposition of claims

A total of 1,376 claims were evaluated; Table 2 shows the disposition of these claims.

Medical misadventure

Medical liability insurers classify claims by the “misadventure” that allegedly occurred. These are listed in Table 3.

Indemnity payments

Analysis of average and median indemnity payments did not yield any significant differences with respect to diagnosis or medical misadventure. The average indemnity (all diagnoses) for a paid claim was $327,951. The largest payout was $2,900,000.

Medicolegal aspects of surgical complications

Medical literature contains little discussion or analysis of the relationship between surgical complications and malpractice claims. Although there is some coverage in legal forums, the discussion centers on precedental value, establishing rules of law and not attesting to the quality of medical care.3 In one review of 109 malpractice claims involving the lumbar spine, 29 different complication categories were identified (some claims had more than one complication).3 The most common complications according to this review are listed in Table 4.

With regard to the cervical spine, a new neurologic deficit was by far the most common complication cited, providing the basis for 64 percent of the suits in one series.4 Other common reasons for suits involving the cervical spine included delay or failure to diagnose, lack of informed consent, use of a device that had not yet received approval from the Food and Drug Administration (specifically lateral mass plates) and pain and suffering.4

Specific Complications

Dural tear—Unintended incidental durotomy is one of the most common complications of lumbar spine surgery. In one study of 146 malpractice cases, it ranked second behind cauda equina syndrome as an alleged complication (23 cases).5 In each case, the durotomy was accompanied by an associated complication or sequelae (Table 5).

The incidence of unintended durotomy during spinal surgery is estimated to be 0.3 percent to 13 percent, rising to 17.6 percent during reoperative cases.5 Although incidental durotomy is considered a benign occurrence, a subset of patients with intraoperative dural tears will have new or worsened neurologic deficits. A 1989 long-term follow-up study of 17 patients with incidental durotomies found no significant difference in new or worsening neurologic symptoms.6 But a more recent 2005 study demonstrated a poorer long-term outcome in patients with dural tears, contrary to the findings of previous authors.7

Although rarely the sole basis for a claim, incidental durotomies with associated sequelae appear to be a common factor prompting lawsuits. The risk of durotomy and its potential sequelae should be discussed with the patient during the consent process. At the time of surgery, the surgeon should repair any apparent durotomy, if possible. The patient should be notified of the occurrence and carefully monitored and treated for any sequelae.

Wrong level—Operating at the wrong-level disc is a rarely discussed issue, but nonetheless occurs with relative frequency and is often the basis of a malpractice suit. Wrong-level disc surgery is the second most common reason for reoperation for a herniated disc (recurrent disc herniation being the most common reason).8 In the data used for this study, wrong-site surgery was the fourth most common medical misadventure, with a very high rate of paid claims (Table 3). Similarly, Goodkin and Laska reported on a series of malpractice claims for wrong-level surgeries in which 81 percent resulted in either a settlement or jury verdict for the plaintiff.8

Reasons for wrong-level disc surgery include:

• No localizing radiographs or fluoroscopy obtained

• Misinterpretation of localizing studies because of congenital variation (i.e. transitional anatomy), inadequate radiographic exposure or incorrect counting

• Inadequate radiographic visualization because of large body habitus or operating table limitations

• Failure to recognize that operated level does not demonstrate the expected pathology8

The surgeon should discuss the potential of wrong-site surgery with the patient, especially if risk factors such as a large body habitus exist.8

Vascular and visceral injuries—Vascular and visceral injuries secondary to perforation of the anterior annulus fibrosis represent some of the most lethal complications that the spine surgeon encounters. Vascular injuries (aorta, vena cava or iliac vessels) are estimated to occur at a rate of 1.6 to 17 per 10,000 cases,9,10 with an associated mortality of 15 percent to 62 percent.9 Additionally, visceral injuries are estimated to occur in 3.8 of 10,000 cases. 11 These include injuries to the bowel, ureter, bladder and pancreas. 9 In a review of 21 malpractice claims (18 vascular and 3 visceral injuries), the plaintiff was successful nearly half (48 percent) of the time.9

Surgeons are often unaware that they have breached the anterior annulus or that there has been a vascular or visceral injury,9,12 because the telltale brisk bleeding associated with most large vessel injuries often does not occur. Despite the ominous nature of these injuries, their occurrence is not considered ipso facto evidence of negligence. The standard of care with these injuries rests with the recognition and treatment of the complication rather than the occurrence itself.9

Unexplained bleeding or hypotension are reasons to suspect a vascular or visceral injury. If the surgeon suspects such an injury, immediate steps should be taken to obtain diagnostic studies or intra-abdominal exploration.13

Some controversy exists over informed consent with regard to these injuries. Some surgeons consider these injuries so rare that they do not warrant inclusion in the consent process other than in the general discussion of death. Other surgeons feel that it is much easier to explain an unplanned abdominal incision to the patient if the potential complication was mentioned preoperatively.9

Cauda equina syndrome—In the medical malpractice arena, cauda equina syndrome can manifest itself as a postoperative complication, or present de novo as the sequela of a lumbar disc herniation or other pathology. As a postoperative complication, cauda equina syndrome is a rare problem, with an occurrence of 0.002 percent to 0.3 percent after lumbar spine surgery.14-16 In a review of 20 medical liability claims with a postoperative cauda equina syndrome, six were associated with a cerebral spinal fluid leak and four were associated with an epidural hematoma.3 Sixteen of the 20 cases had a settlement or jury verdict for the plaintiff. Courts have been divided as to the issue of informed consent, specifically with regards to bowel and bladder incontinence.3 Because variations exist from state to state, it is prudent to discuss these complications during the consent process.

Cauda equina syndrome has an incidence of 2.2 percent to 3.2 percent following lumbar disc herniation.17 This syndrome is the basis for medical liability claims for several reasons. Failure to recognize the syndrome and failure to act promptly are commonly cited. Recognizing the syndrome is the responsibility of the emergency department physician as well as the consultant spine surgeon. A thorough history and physical exam, including documentation of rectal tone and peri-anal sensation, are crucial to making the diagnosis.17 Additionally, nursing staff who are charged with performing neurologic exams are responsible for reporting changes in motor or visceral functions and incontinence. Patients at risk of cauda equina syndrome who complain of worsening pain should be asked about their bladder function and examined if the diagnosis is suspected.

New neurologic deficit—During lumbar surgery, the incidence of motor root damage resulting in paresis has been estimated at 0.5 percent to 9.3 percent, with the L5 nerve root being the most commonly injured root.18,19 In their review of 109 malpractice cases, Goodkin and Laska identified 15 cases of nerve root injury—14 resulting in foot drop and one resulting in loss of plantar flexion.5 One-third of these cases had an associated dural tear. The majority of these cases (8 of 15) were resolved in favor of the plaintiff.

New neurologic deficits after cervical spine surgery are very diverse in presentation, ranging from complete quadriplegia to an isolated nerve root irritation. Additionally, injury to the recurrent laryngeal nerve and to the cervical sympathetic chain are known complications. The data that we reviewed did not show any meaningful correlation between the type of injury and subsequent litigation.

Retained surgical sponges—In the medicolegal realm, a retained surgical sponge is a classic example of res ipsa loquitur (the injury speaks for itself), with the majority of cases ruled or settled in favor of the plaintiff. In our analysis, four of five cases were settled for the plaintiff. In similar fashion, another series had two of three cases resolved in favor of the plaintiff.5

Perioperative ischemic optic neuropathy (POION)—Despite its relative rarity, perioperative vision loss after spine surgery garners considerable interest in the medicolegal forum. Reports list an incidence of up to 0.12 percent for spine surgery; POION is more common after surgery in the prone position.20 Additional risk factors are intraoperative hypotension, anemia and a prolonged procedure. Recent authors have recommended that all patients undergoing spine surgery should be informed about the low but definite risk of this devastating and untreatable complication.20

Informed consent—In their review of 1,810 closed claims against orthopaedists, Bhattacharyya et al found that 28 (1.5 percent) involved informed-consent issues.21 Of those, nine (32 percent) involved spine surgery. Data reviewed in our survey identified “consent issues, breach of contract or warranty” as an associated issue in 140 cases, 39 of which were paid claims. Because we did not have access to the medical and legal records, it was impossible to characterize the nature and extent of the “consent issue.”

We found a higher rate of consent issues than other authors,21,22 demonstrating the importance of obtaining an appropriate and complete informed consent prior to surgery. Bhattacharyya et al found that two processes significantly reduced the indemnity risk associated with informed consent.21 The surgeon should document the consent process in the office notes and obtain the consent in the office, not in the hospital ward or preoperative holding area.

Summary

Our review of 10 years of malpractice claims related to spine surgery showed no significant difference in the rate at which claims were paid relative to the underlying diagnosis. Of the 1,376 claims evaluated, 25 percent resulted in some payment to the plaintiff. Improper performance of a surgical procedure and diagnosis error were the most commonly cited medical misadventures and resulted in the majority of paid claims. The most common form of claim resolution was settlement, resulting in payment in 47 percent of cases. In claims that proceeded to a jury, the verdict favored the defendant 84 percent of the time.

Bryan A. Fox, MD, and William J. Richardson, MD, are members of the division of orthopaedic surgery, Duke University Medical Center. Dr. Fox can be reached at bslyfox@cox.net; Dr. Richardson can be reached at richa015@mc.duke.edu

References

1. Klimo GF, Daum WY, Brinker MR, McGuire E, Elliott M. Orthopedic medical malpractice: An attorney’s perspective. Am J Ortho 2000;29(2):93-97.

2. American Academy of Orthopaedic Surgeons. Managing Orthopaedic Malpractice Risk. Second edition. Rosemont Ill: American Academy of Orthopaedic Surgeons: 2000.

3. Goodkin R, Laska LL. In: Hardy R, ed. Lumbar Disc Disease. Second edition. New York: Raven, 1993:331-349.

4. Epstein NE. It is easier to confuse a jury than convince a judge: The crisis in medical malpractice. Spine 2002;27(22):2425-2430.

5. Goodkin R, Laska LL. Unintended “Incidental” Durotomy During Surgery of the Lumbar Spine: Medicolegal Implications. Surg Neurol 1995;43:4-14.

6. Jones AA, Stambough JL, Balderston RA, Rothman RH, Booth RE. Long-term results of lumbar spine surgery complicated by unintended incidental durotomy. Spine 1989;14(4):443-446.

7. Saxler G, Krämer J, Barden B, Kurt A, Pförtner J, Bernsmann K. The long-term sequelae of incidental durotomy in lumbar disc surgery. Spine 2005;30(20):2298-2302.

8. Goodkin R, Laska LL. Wrong disc space level surgery: Medicolegal implications. Surg Neurol 2004;61:323-342.

9. Goodkin R, Laska LL. Vascular and visceral injuries associated with lumbar disc surgery: Medicolegal implications. Surg Neurol 1998;49:358-372.

10. DeSaussare RL. Vascular injury coincident to disc surgery. J Neurosurg 1959;16:222-229.

11. Smith EB, Hanigan WC. Injuries to the intra-abdominal viscera associated with lumbar disk excision. In: Tarlov EC, ed. Neurosurgical Topics: Complications of Spinal Surgery. Park Ridge Ill: American Association of Neurological Surgeons, 1991:41-49.

12. Harbison HB. Major vascular complications of intervertebral disc surgery. Annals Surg 1954;140:342-348.

13. Freeman DG. Major vascular complications of lumbar disc surgery. West J Surg, Obstet Gynecol 1961;69:175-177.

14. Oppel F, Schramm J, Schirmer M, Zeitner M. Results and complicated course after surgery for lumbar disc herniation. Adv Neurosurg 1977;4:36-51.

15. Spangfort EV. The lumbar disc herniation: A computer-aided analysis of 2,504 operations. Acta Orthop Scand (Suppl) 1972;142:1-95.

16. McLaren AC, Bailey SI. Cauda equina syndrome: A complication of lumbar discectomy. Clin Orthop 1986;204:143-149.

17. Kostuik JP. Medicolegal consequences of cauda equina syndrome: An overview. Neurosurg Focus 2004;16(6):39-41.

18. Horwitz NH, Rizzoli HV. Herniated intervertebral discs and spinal stenosis. In: Horwitz NH, Rizzoli HV, eds. Postoperative Complications of Extracranial Neurological Surgery. Baltimore: Williams and Wilkins, 1987:30-72.

19. Schepelmann F, Greiner L, Pia HW. Complications following operation of lumbar discs. Adv Neurosurg 1977;4:52-54.

20. Chang SH, Miller NR. The incidence of perioperative ischemic optic neuropathy associated with spine surgery. Spine 2005;30(11):1229-1302.

21. Bhattacharyya T, Yeon H, Harris M. The medico-legal aspects of informed consent in orthopaedic surgery. J Bone Joint Surg Am 2005;87A(11):2395-2400.

22. Hickson GB, Federspiel CF, Pichert JW. Patient complaints and malpractice risk. JAMA 2002;287:2951-2957.

Table 1. Closed and paid claims for various diagnoses

Diagnosis (ICD-9)

Closed claims

Paid claims

Percentage of closed claims paid

Displacement of lumbar or thoracic disc with or without myelopathy (722.1)

538

120

22

Displacement of cervical disc with or without myelopathy (722.0)

223

57

25

Spinal stenosis, other than cervical (724)

89

23

26

Fracture of vertebral column without spinal cord injury (805)

88

20

23

Acquired and degenerative spondylolisthesis (738.4)

72

15

21

Kyphosis and scoliosis (737.3)

68

22

32

Cervical spinal stenosis (723.0)

57

16

28

Cervical spondylosis with or without myelopathy (721)

41

8

20

Lumbar intervertebral disc disorder with myelopathy (722.73)

38

11

29

Degeneration of cervical intervertebral disc (722.4)

38

8

21

Cervical spondylosis with myelopathy (721.1)

34

11

32

Cervical intervertebral disc disorder with myelopathy (722.71)

31

14

24

Fracture of vertebral column with spinal cord injury (806)

26

7

27

Lumbosacral spondylosis without myelopathy (721.3)

22

5

23

Thoracic intervertebral disc disorder with myelopathy (722.72)

6

1

17

Degeneration of thoracic or lumbar disc (722.5)

5

2

40

Table 2. Disposition of claims

Disposition

Closed claims

(Percentage of total claims)

Paid claims

(Percentage of total claims)

Settlement

557 (40)

264 (19)

Before litigation

283 (21)

26 (2)

Suit filed but not prosecuted

217 (16)

7 (0.5)

Dismissal

181 (13)

7 (0.5)

Judgment for defendant

80 (6)

0

Mediation

25 (2)

21 (2)

Judgment for plaintiff

15 (1)

15 (1)

Judgment for defendant after appeal

8 (0.5)

0

Directed verdict for defendant

5 (0.4)

0

Other

5 (0.4)

4 (0.3)

Table 3. Medical misadventure

Medical misadventure

Closed claims

Paid claims

Percentage of closed claims paid

Improper performance

474

123

26

None

250

10

4

Diagnosis error

196

53

27

Wrong patient/body part

54

35

63

Failure to recognize a complication

54

12

22

Failure to supervise/monitor case

42

11

26

Not indicated

34

9

26

Medication error

19

8

42

Positioning

18

6

33

Improper supervision of staff and other personnel

18

2

11

Failure/delay in referral

14

4

29

Delay in performance

8

6

75

Problem with patient monitoring

7

3

43

Error in agent use

6

3

50

Surgical foreign body

5

4

80

Failure to instruct or communicate with patient

4

0

0

Intubation problems

3

1

33

Surgical clearance

3

0

0

Table 4. Complications in medical liability cases involving lumbar spine

Complication

Number of Cases

Dural tear

20

Cauda equina syndrome

20

Foot drop

14

Death

9

Wrong level

9

Vascular injury

7

Wound infection

6

Meningitis

6

Postoperative hematoma

4

Intraspinal protruding bone plug

4

Bladder and/or bowel dysfunction

3

Did not receive desired result

3

Missed fragment

3

Retained sponge

3

Peripheral nerve injury

2

Failure to diagnose/wrong diagnosis

2

Disc space collapse

2

Source: Goodkin R, Laska LL. In: Hardy R, ed. Lumbar Disc Disease. Second edition. New York: Raven, 1993;331-49.

Table 5. Complications and sequelae of incidental durotomies

Complications and sequelae

Number of cases

Nerve root injury

8

Cauda equina syndrome

7

Pain

7

Cerebrospinal fluid leak

6

Arachnoiditis

4

Pseudomeningocele

3

Bowel/bladder dysfunction

2

Infection

2

Other

4

Source: Goodkin R, Laska LL. Unintended “Incidental” Durotomy During Surgery of the Lumbar Spine: Medicolegal Implications. Surg Neurol 1995;43:4-14.


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