Cauda Equina Syndrome

Secondary to Lumbar Disc Herniation

A Meta Analysis of Surgical Outcomes

Spine Vol 25 No. 12 pp1523-1532

Introduction

• Definition of CES as a severe neurological deficit with clinical features of low back pain, sciatica, saddle anaesthesia, motor weakness, sensory deficit, urinary incontinence.

• CES is the primary absolute indication for the acute surgical treatment of lumbar disc herniation

• There have been small studies recommending early rather than late decompression but others saying that late surgery can give satisfactory outcomes

• Purpose of this study was to increase the statistical power of previous studies in the English literature of CES caused by herniated lumbar disc.

• The aims were to

• Find specific preoperative variables which are significantly associated with good or bad post op outcomes

• Determine whether there is a correlation between the time of surgery after onset of CES and outcomes of surgery

Materials and Methods

• MEDLINE search from Jan 1966 to May 1999

• Eligible studies (42 papers out of 104)

• A collection of patients was only included if the following preop and post op variables were known

Preop variables	Post op variables
Age	Resolution of pain
Gender	Resolution of sensory deficit
Occupation	Resolution of motor deficit
History of previous spinal surgery	Resolution of urinary incontinence
History of chronic low back pain	Resolution of sexual dysfunction
Duration of chronic back pain prior to CES	Resolution of rectal dysfunction
History of trauma with onset of CES
Sudden onset of CES
Presence of sciatica with CES
Preop weakness of legs
Preop sensory deficit
Preop loss of reflexes
Preop rectal dysfunction
Length of time to surgery from onset of CES

• Univariate logistic regression analysis was used to compare each post op outcome with preop variables

• Analysis of time to surgery was performed separately

• 5 groups were constructed

  1. <24>

  2. 24-48 hrs

  3. 2-10 days

  4. 11 days to 1 month

  5. More than 1 month

• Time of onset of CES defined as time of onset of sphincter disturbance

• Resolution of sensory and motor deficits defined as complete recovery.

• Partial recovery of deficits recorded as a failure to resolve

Results

• 322 patients

• 69% sudden onset

• 82 % chronic low back pain

• Trauma in 62% of cases

• Significant associations

  • Worse prognosis for urinary incontinence if patient had preop chronic lower back pain. (11 x the risk) or preop rectal dysfunction

  • Prognosis for rectal function worse with a history of preop chronic low back pain (25 x the risk)

  • Prognosis for return of sensory deficit worse if preop rectal dysfunction present (1.15x the risk)

  • Older patients had a worse prognosis for sexual dysfunction (by 2.6x if older by 10yrs)

• Times to decompression

  • Better outcome in those decompressed before 48 hrs than those after 48 hours

  • No significant difference in outcome between those decompressed at <>

  • No significant difference in outcome between all three groups decompressed at > 48 hrs

Discussion

• Comparison of the above results with smaller studies are consistent although the smaller studies do not show statistical significance

• Acknowledgement that the follow ups in the papers included did vary, and recovery from cauda equina can occur up to 5 years after surgery

• Acknowledgement that different operative procedures were used

• Acknowledgement of the problems of metaanalysis- different studies report results in different ways, some more objectively than others, some were prospective, some retrospective