Secondary Logo

Journal Logo

Literature Review

Outcomes Reported After Surgery for Cauda Equina Syndrome

A Systematic Literature Review

Srikandarajah, Nisaharan MRCS, MBBS; Wilby, Martin FRCS, PhD; Clark, Simon FRCS, PhD; Noble, Adam CPS, PhD; Williamson, Paula PhD; Marson, Tony FRCS, MD

Author Information
doi: 10.1097/BRS.0000000000002605


Cauda equina syndrome (CES) is mainly caused by compression of the lumbosacral nerve roots below the conus medullaris. Clinically, symptoms and signs include low-back pain, saddle anesthesia, unilateral or bilateral sciatica, and motor weakness of the lower extremities with bladder and bowel dysfunction.1,2 However, CES is a clinical-radiological diagnosis as clinical signs are not particularly sensitive to a CES diagnosis.3,4 A lumbo-sacral magnetic resonance imaging (MRI) is required for diagnosis. Gleave and McFarlane5 stressed the importance of categorizing CES into CES incomplete (CESI) and CES complete with urinary retention (CESR) (Figure 1). It is deemed a surgical emergency and there have been numerous publications and debates relating to the ideal timing for surgery.6–9 It can result in permanent damage to nerve roots resulting in long lasting or permanent disabling symptoms.2

Figure 1
Figure 1:
Symptoms relating to CESI and CESR.

There is no consultation with patients in the literature regarding importance of outcomes for CES. In addition, there is little known about the long-term outcomes, which was highlighted by Korse et al,10 who independently decided to focus on outcomes of micturition, defecation, and sexual function. Bias in studies, lack of universal definitions, and incomplete follow-up data were seen in this systematic review.

The problems with not having a core outcome set (COS) includes:

  • (i) Patients are not included so important outcomes to them may not be measured. This has been witnessed in other healthcare areas such as childhood asthma and esophageal cancer.11–14
  • (ii) Lack of a consistent approach makes individual studies difficult to interpret and put into context of other studies.
  • (iii) Possibility for synthesizing evidence in a systematic review and meta-analysis are diminished 15.
  • (iv) Waste and inefficiency. It is reported that 85% of research funding is wasted across the research cycle with key sources related to outcomes; important outcomes are not assessed, published research fails to set its position when compared with all previous similar research and 50% of planned study outcomes are not reported.16

At present, there is no COS for CES, which is to the detriment of patients and health services. The aim of this systematic literature review is to inform the future development of a COS by identifying all documented outcomes for patients after surgery in CES, identify if they are defined, and to assess what variability there is. The systematic literature review is the first step to inform the development of a COS14 for patients who have undergone surgery for CES to be used in research and in practice.


This study has been registered as 824 on the COMET (Core Outcome Measures in Effectiveness Trials) website ( Table 1 lists the inclusion criteria applied to the search strategy.

Inclusion Criteria for the Systematic Literature Review

Search Strategy

We searched Medline, Embase, and CINAHL Plus (Cumulative Index to Nursing and Allied Health Literature). The search strategy for each database is available in Appendix 1, Online trial registries included Clinical, EU clinical trials registry and the ISRCTN (International Standard Randomized Controlled Trials Number) registry. The trial registries were searched for any completed or ongoing trials in surgery for CES and no relevant studies were found. Only case reports and abstracts were excluded in the initial search term as we wanted studies with five or more patients. We only included studies published after January 1, 1990 to keep investigation (post-MRI era) and surgical management of CES in line with current medical practice. Citations were collated with Endnote X7 referencing program (Thomson Reuters, New York, NY) and duplicates removed.

Data Extraction

Titles and abstract were initially screened by NS to identify potential studies for inclusion, for which full text articles were obtained for further assessment. Approximately, 10% of included articles were randomly checked for suitability by clinical supervisors and any discussion regarding uncertainty of eligibility criteria applied to the search results was discussed with them (SC, MW, and TM). A data extraction form was used to collect data on study design and location, patient demographics, timing of operation, definition of CES, diagnosis, etiology, surgical procedure, follow-up duration, outcome terminology, outcome definition, and assessment tool.


Below are the definitions for the main terms used in the analysis of this systematic literature review.

  • 1. Core outcome domain- The overall category to which similar subdomains and outcomes are listed under. The outcome domains that we have used in this article have been linked to the high level set of outcome categories used for annotation of Cochrane reviews17 ( and through discussion with the COMET initiative team. These are listed in bold in Table 3.
  • 2. Subdomain- A subcategory of a Core outcome domain to which similar outcomes are listed under. These are listed in normal script in Table 3.
  • 3. Outcome- An outcome documented in an article after a patient has had an operation for CES. For example, nervous system (core outcome domain)> bladder function (subdomain)> urinary incontinence (outcome).
  • 4. Variations- Variations were also documented, which means the number of different terms used to define a core outcome domain or subdomain. An example of a variation is given in the superscript of Table 4.
  • 5. Outcome definition- this was categorized as “no definition” or “definition present.” If a definition was present it could be subjectively a complete or partial definition but was recorded as “definition present.” “No definition” indicates the outcome domain was mentioned with no accompanying definition in the article or assessment tool. An example of how outcome definition was done is given in the superscript of Table 4.

Core Outcome Domains (in Bold) and Subdomains
Raw Data for Each Outcome Showing How Many Studies Each Outcome is Reported in, the Total Number of Outcomes, the Variations for Each Outcome, if a Definition is Present in the Reported Studies and the Number of Assessment Tools for the Reported Outcomes. Outcomes are Listed in Order of Decreasing Frequency of Reported Studies


A total of 1873 articles were identified by electronic database searches.

  • 1. Medline (650)
  • 2. Embase (949)
  • 3. CINAHL Plus (239)
  • 4. Registries (35) included Clinical (5), EU clinical trials registry (12) and ISRCTN (International Standard Randomized Controlled Trials Number) registry (18).

The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) flowchart in Figure 2 shows the process during the systematic literature review. Following inclusion criteria in Table 1 resulted in 1838 articles plus the 35 studies from the online registry search giving a total of 1873 studies. Moreover, 10% of included studies were reviewed by a supervisor (MW and SC) to assess if inclusion criteria had been applied adequately and agreement was achieved after discussion amongst us. Uncertainty regarding eligibility of certain full text articles for inclusion were discussed with the clinical supervisory team (MW, SC, and TM) and settled leading to 61 included articles. Thirty-four articles were excluded after the full text was obtained and the reasons for this were given as in Figure 2.

Figure 2
Figure 2:
PRISMA flowchart for online databases.

Summary details, patient demographics, and how many studies they were reported in out of the 61 included studies are detailed in Table 2. Most studies (90.2%) were retrospective. CES was not defined in 20 studies (32.8%). Even in the articles where CES is defined there were many differing definitions. The most common definition was CESI and CESR as described in Figure 1.

Summary Characteristics and Demographics of Included Studies

A total of 737 outcomes were reported in the 61 included articles.9,18–78 For ease of analysis in this study, these reported outcomes have been categorized to one of the 20 core outcome domains (Table 3). The nervous system core outcome domain had 10 subdomains, and the physical functioning has two subdomains (Table 3). The number of different variations in the description of outcomes can be seen in Table 4 linked to the outcome domains.

Figure 3 shows the number of articles in which specific outcomes were reported. Bladder function, motor function, sensation, bowel function, leg pain, and lower-back pain were the most commonly reported in descending order. They are all within the nervous system core outcome domain. Moreover, for each outcome, the number of articles where it is defined and not defined is documented. Figure 3 also shows the number of articles where the reported outcome had an assessment tool or not.

Figure 3
Figure 3:
Stacked bar chart showing total number of articles where the outcome was reported and the proportion of those defined (blue) and those not defined (red). Moreover for each outcome the number of articles which have used an assessment tool for a reported outcome (green) and the number that have not (orange). Outcomes are listed from most to least reported.

Table 4 shows the raw data for each outcome showing how many studies each outcome is reported in, the total number of outcomes, the number of variations in the description of the outcome if a definition is present or not in the reported studies, and the number of assessment tools for the reported outcome. Table 5 shows the various assessment tools used for each outcome.

Assessment Tools are Listed in Alphabetical Order for the Corresponding Reported Outcomes


This systematic review shows that there is significant heterogeneity in the outcomes measured for patients who have undergone surgery for CES with no consensus.

Most of the evidence regarding outcomes for CES patients after surgery is derived from level 4 evidence, namely, single centre retrospective cohort review studies. The average data collection period was over 8 years with a median number of 14 patients per study, which highlights the rare nature of the condition and difficulty in collecting meaningful data retrospectively. This feeling is also echoed by Todd and Dickson, 2016.79 Since 1990, the number of publications analyzing outcomes after an operation for CES have increased with the most being produced in the last 5-year period (43.5%). Median follow up was at 31 months reflecting the deficiency in the literature for any long-term outcomes.

The main investigation is MRI, which reflects the systematic literature review focusing on studies from 1990 onwards. Before this there may have been a reliance on myelography and CT to radiologically identify CES compression. The main etiology is disc herniation. There are no studies in the literature documenting the exact distribution of CES aetiology but the most common cause is believed to be because of disc herniation.

Poor definition of CES has been previously highlighted in a systematic review of the literature.80 Twenty studies (32.8%) did not define this and of the 41 studies where a definition was present, there was significant heterogeneity in the definitions. The most common definition for CES in this review was CESI and CESR.5 If a study fails to define CES then we are unsure of the condition to which the outcomes of the study belong to.

Most common surgical method in studies was a laminectomy and discectomy as seen in Table 2 but there were other studies that predominantly performed surgery via a microdiscectomy. Laminectomy alone, or with instrumentation was also mentioned for CES patients. In fact, now there is an increase in the popularity of endoscopic lumbar discectomy procedure 45 that adds to the range of procedures available when dealing with CES secondary to disc herniation. There is no consensus in the literature as to a specific decompressive procedure to be used for CES secondary to compressive pathology. This is also another factor that may affect outcomes for these patients.

In total, there were 737 outcomes reported verbatim and categorized into 20 core outcome domains and 12 subdomains. Instead of the same term being used for each outcome, there exists 507 variations in terminology (Table 4). In addition, most of the outcomes in the included articles have no definition. Except bladder function, adverse events, need for intervention, and global quality of life, all other outcomes had “no definition” in the majority of the included articles (Figure 3). This highlights that there is significant heterogeneity in not only the outcome terminology used but the level to which it is defined in the literature. Except global quality of life, emotional functioning, role functioning, and social functioning, most outcomes did not have an assessment tool in most of the articles (Figure 3). Fourteen of the outcome domains/subdomains we categorized had multiple different assessment tools used for each of them as seen in Table 5. There is a lack of uniformity over which assessment tool is best suited for each outcome in the literature. If outcomes are being measured with different scales, scoring systems, and questionnaires then it would be difficult to synthesize these results for meaningful analyses.

There is significant heterogeneity of the outcomes for patients who have undergone an operation for CES, how they are defined and measured in the literature. Bladder function, motor function, sensation, bowel function, leg pain and lower-back pain outcomes are the most reported. They are all physiological core domains, which have been prioritized in the literature over the other core domains that relate to life impact, mortality, resource use, and adverse events. However, there has not been consultation with key stakeholders regarding what outcomes are the most important to be justifying this practice. Involvement of key stakeholders through an iterative process has been employed in Rheumatology through OMERACT (Outcome MEasures in Rheumatology) and in Women's Health through the CROWN (CoRe Outcomes in Women's and Newborns health) initiative 81,82 (; They have come a long way from developing COS to achieving a level of homogeneity among similar studies to increase the quality and yield of their research. This needs to be achieved for patients who have undergone surgery for CES.


The systematic literature review was carried out by the main author (NS). Uncertainties and discrepancies were discussed with the research team (PRW, TM, MW, SC, and AN). Only English language articles were included. It would have been beneficial to have another independent group conduct the search strategy and data extract independently and to compare the results achieved. Because of the limitation of resources this was not performed.


There is significant heterogeneity in outcomes reported for studies after surgery for CES patients and the methods by which they are measured. This indicates a clear need for the development of a COS and the results of this systematic literature will be combined with the results of outcomes sourced from CES patients in qualitative interviews. All outcomes will then be prioritized through a Delphi process and consensus meeting to develop a core list of outcomes determined to be of most importance by key stakeholders.

Key Points

  • For patients who have had an operation for CES there are inconsistencies in the outcomes reported, defined, and assessed between studies.
  • Because of the heterogeneity of outcomes reported, defined, and assessed we are unable to synthesize the results for a meta-analysis.
  • The outcomes have not been validated in the literature by key stakeholders as being important to them.


1. Kostuik JP. Controversies in cauda equina syndrome and lumbar disk herniation. Curr Opin Orthop 1993; 4:125–128.
2. Gardner A, Gardner E, Morley T. Cauda equina syndrome: a review of the current clinical and medico-legal position. Eur Spine J 2011; 20:690–697.
3. Balasubramanian K, Kalsi P, Greenough CG, et al. Reliability of clinical assessment in diagnosing cauda equina syndrome. Br J Neurosurg 2010; 24:383–386.
4. Bell D, Collie D, Statham P. Cauda equina syndrome: what is the correlation between clinical assessment and MRI scanning? Br J Neurosurg 2007; 21:201–203.
5. Gleave J, Macfarlane R. Cauda equina syndrome: what is the relationship between timing of surgery and outcome? Br J Neurosurg 2002; 16:325–328.
6. Ahn UM, Ahn NU, Buchowski JM, et al. Cauda equina syndrome secondary to lumbar disc herniation: a meta-analysis of surgical outcomes. Spine (Phila Pa 1976) 2000; 25:1515–1522.
7. Kohles SS, Kohles DA, Karp AP, et al. Time-dependent surgical outcomes following cauda equina syndrome diagnosis: comments on a meta-analysis. Spine (Phila Pa 1976) 2004; 29:1281–1287.
8. Todd N. Cauda equina syndrome: the timing of surgery probably does influence outcome. Br J Neurosurg 2005; 19:301–306.
9. Srikandarajah N, Boissaud-Cooke MA, Clark S, et al. Does early surgical decompression in cauda equina syndrome improve bladder outcome? Spine (Phila Pa 1976) 2015; 40:580–583.
10. Korse N, Jacobs W, Elzevier H, et al. Complaints of micturition, defecation and sexual function in cauda equina syndrome due to lumbar disk herniation: a systematic review. Eur Spine J 2013; 22:1019–1029.
11. Sinha IP, Williamson PR, Smyth RL. Outcomes in clinical trials of inhaled corticosteroids for children with asthma are narrowly focussed on short term disease activity. PLoS One 2009; 4:e6276.
12. Sinha IP, Smyth RL, Williamson PR. Using the Delphi technique to determine which outcomes to measure in clinical trials: recommendations for the future based on a systematic review of existing studies. PLoS Med 2011; 8:e1000393.
13. Avery K, Chalmers K, Whale K, et al. The importance of stakeholder selection in core outcome set development: how surveying different health professionals may influence outcome selection. Trials 2015; 16:47.
14. Williamson PR, Altman DG, Blazeby JM, et al. Developing core outcome sets for clinical trials: issues to consider. Trials 2012; 13:132.
15. Jones J, Hunter D. Consensus methods for medical and health services research. BMJ 1995; 311:376.
16. Chalmers I, Glasziou P. Avoidable waste in the production and reporting of research evidence. Obstet Gynecol 2009; 114:1341–1345.
17. Davey J, Turner RM, Clarke MJ, et al. Characteristics of meta-analyses and their component studies in the Cochrane Database of Systematic Reviews: a cross-sectional, descriptive analysis. BMC Med Res Methodol 2011; 11:160.
18. Akbar A, Mahar A. Lumbar disc prolapse: management and outcome analysis of 96 surgically treated patients. J Pak Med Assoc 2002; 52:62–65.
19. Allegretti L, Mavilio N, Fiaschi P, et al. Intra-operative vertebroplasty combined with posterior cord decompression a report of twelve cases. Interv Neuroradiol 2014; 20:583–590.
20. Aly TA, Aboramadan MO. Efficacy of delayed decompression of lumbar disk herniation causing cauda equina syndrome. Orthopedics 2014; 37:e153–e156.
21. Arrigo RT, Kalanithi P, Boakye M. Is cauda equina syndrome being treated within the recommended time frame? Neurosurgery 2011; 68:1520–1526.
22. Ayoub MA. Displaced spinopelvic dissociation with sacral cauda equina syndrome: outcome of surgical decompression with a preliminary management algorithm. Eur Spine J 2012; 21:1815–1825.
23. Baba H, Maezawa Y, Furusawa N, et al. The role of calcium deposition in the ligamentum flavum causing a cauda equina syndrome and lumbar radiculopathy. Paraplegia 1995; 33:219–223.
24. Beculic H, Skomorac R, Jusic A, et al. Impact of timing on surgical outcome in patients with cauda equina syndrome caused by lumbar disc herniation. Med Glas (Zenica) 2016; 13:136–141.
25. Bejia I, Younes M, Zrour S, et al. Factors predicting outcomes of mechanical sciatica: a review of 1092 cases. Joint Bone Spine 2004; 71:567–571.
26. Bellabarba C, Schildhauer TA, Vaccaro AR, et al. Complications associated with surgical stabilization of high-grade sacral fracture dislocations with spino-pelvic instability. Spine (Phila Pa 1976) 2006; 31 (11S):S80–S88.
27. Božić B, Kogler A, Negovetić L, et al. Sequestred extrusion of lumbar disc: experimental model, clinical picture, diagnosis and treatment. Acta Clin Croat 2003; 42:213.
28. Buchner M, Schiltenwolf M. Cauda equina syndrome caused by intervertebral lumbar disk prolapse: mid-term results of 22 patients and literature review. Orthopedics 2002; 25:727–731.
29. Busse JW, Bhandari M, Schnittker JB, et al. Delayed presentation of cauda equina syndrome secondary to lumbar disc herniation: functional outcomes and health-related quality of life. CJEM 2001; 3:285–291.
30. Crocker M, Fraser G, Boyd E, et al. The value of interhospital transfer and emergency MRI for suspected cauda equina syndrome: a 2-year retrospective study. Ann R Coll Surg Engl 2008; 90:513–516.
31. Dhatt S, Tahasildar N, Tripathy SK, et al. Outcome of spinal decompression in cauda equina syndrome presenting late in developing countries: case series of 50 cases. Eur Spine J 2011; 20:2235–2239.
32. Domen P, Hofman P, Van Santbrink H, et al. Predictive value of clinical characteristics in patients with suspected cauda equina syndrome. Eur J Neurol 2009; 16:416–419.
33. Duncan JW, Bailey RA. Cauda equina syndrome following decompression for spinal stenosis. Global Spine J 2011; 1:15–18.
34. Ea H-K, Lioté F, Lot G, et al. Cauda equina syndrome in ankylosing spondylitis: successful treatment with lumboperitoneal shunting. Spine (Phila Pa 1976) 2010; 35:E1423–E1429.
35. Foruria X, de Gopegui KR, García-Sánchez I, et al. Cauda equina syndrome secondary to lumbar disc herniation: Surgical delay and its relationship with prognosis. Rev Esp Cir Ortop Traumatol 2016; 60:153–159.
36. Fukui J, Ohotsuka K, Asagai Y. Improved symptoms and lifestyle more than 20 years after untethering surgery for primary tethered cord syndrome. Neurourol Urodyn 2011; 30:1333–1337.
37. Fuso FAF, Dias ALN, Letaif OB, et al. Epidemiological study of cauda equina syndrome. Acta Ortop Bras 2013; 21:159–162.
38. Galasko C. Spinal instability secondary to metastatic cancer. J Bone Joint Surg Br 1991; 73:104–108.
39. Galvin J, Freedman B, Schoenfeld A, et al. Morbidity of early spine surgery in the multiply injured patient. Arch Orthop Trauma Surg 2014; 134:1211–1217.
40. Gooding BW, Higgins MA, Calthorpe DA. Does rectal examination have any value in the clinical diagnosis of cauda equina syndrome? Br J Neurosurg 2013; 27:156–159.
41. Henriques T, Olerud C, Petren-Mallmin M, et al. Cauda equina syndrome as a postoperative complication in five patients operated for lumbar disc herniation. Spine (Phila Pa 1976) 2001; 26:293–297.
42. Hussain S, Gullan R, Chitnavis B. Cauda equina syndrome: outcome and implications for management. Br J Neurosurg 2003; 17:164–167.
43. Kennedy JG, Soffe KE, McGrath A, et al. Predictors of outcome in cauda equina syndrome. Eur Spine J 1999; 8:317–322.
44. KOTİL K, ERAS M, AKÇETİN M, et al. Do the spinal pathologies that accompany lumbar disc disease affect surgical prognosis? Turkish Neurosurg 2006; 16: 4.
45. Li X, Dou Q, Hu S, et al. Treatment of cauda equina syndrome caused by lumbar disc herniation with percutaneous endoscopic lumbar discectomy. Acta Neurol Belg 2016; 116:185–190.
46. Lich Ng LC, Tafazal S, Longworth S, et al. Cauda equina syndrome: an audit. can we do better? J Orthop Med 2004; 26:98–101.
47. Lyons MK, Atkinson JL, Wharen RE, et al. Surgical evaluation and management of lumbar synovial cysts: the Mayo Clinic experience. J Neurosurg 2000; 93:53–57.
48. Marascalchi BJ, Passias PG, Goz V, et al. Comparative analysis of patients with cauda equina syndrome versus an unaffected population undergoing spinal surgery. Spine (Phila Pa 1976) 2014; 39:482–490.
49. McCarthy MJH, Aylott CEW, Grevitt MP, et al. Cauda equina syndrome: factors affecting long-term functional and sphincteric outcome. Spine (Phila Pa 1976) 2007; 32:207–216.
50. McKinley WO, Tellis AA, Cifu DX, et al. Rehabilitation outcome of individuals with nontraumatic myelopathy resulting from spinal stenosis. J Spinal Cord Med 1998; 21:131–136.
51. Morita M, Miyauchi A, Okuda S, et al. Intraspinal epidermoid tumor of the cauda equina region: seven cases and a review of the literature. J Spinal Disord Tech 2012; 25:292–298.
52. Lich Ng LC, Tafazal S, Longworth S, et al. Cauda equina syndrome: an audit. Can we do better? J Orthop Med 2004; 26:98–101.
53. Ökten AI, Özsoy KM, Gezercan Y, et al. Analysis of clinical and surgical outcomes of upper lumbar disk herniations. Neurosurg Q 2015; 25:349–354.
54. Olivero WC, Wang HA, Hanigan WC, et al. Cauda equina syndrome (CES) from lumbar disc herniations. J Spinal Disord Tech 2009; 22:202–206.
55. Podnar S. Cauda equina lesions as a complication of spinal surgery. Eur Spine J 2010; 19:451–457.
56. Qureshi A, Sell P. Cauda equina syndrome treated by surgical decompression: the influence of timing on surgical outcome. Eur Spine J 2007; 16:2143–2151.
57. Raj D, Coleman N. Cauda Equina Syndrome secondary to lumbar disc herniation. Acta Orthop Belg 2008; 74:522–527.
58. Ronen J, Goldin D, Itzkovich M, et al. Outcomes in patients admitted for rehabilitation with spinal cord or cauda equina lesions following degenerative spinal stenosis. Disabil Rehabil 2005; 27:884–889.
59. Sakai Y, Matsuyama Y, Katayama Y, et al. Spinal myxopapillary ependymoma: neurological deterioration in patients treated with surgery. Spine (Phila Pa 1976) 2009; 34:1619–1624.
60. Sapkas GS, Mavrogenis AF, Papagelopoulos PJ. Transverse sacral fractures with anterior displacement. Eur Spine J 2008; 17:342–347.
61. Schebesch K-M, Albert R, Brawanski A, et al. Urgent discectomy: clinical features and neurological outcome. Surg Neurol Int 2016; 2016:17.
62. Schildhauer TA, Bellabarba C, Nork SE, et al. Decompression and lumbopelvic fixation for sacral fracture-dislocations with spino-pelvic dissociation. J Orthop Trauma 2006; 20:447–457.
63. Sengoz A, Kotil K, Tasdemiroglu E. Posterior epidural migration of herniated lumbar disc fragment Clinical article. J Neurosurg Spine 2011; 14:313–317.
64. Shapiro S. Cauda equina syndrome secondary to lumbar disc herniation. Neurosurgery 1993; 32:743–747.
65. Shapiro S. Medical realities of cauda equina syndrome secondary to lumbar disc herniation. Spine (Phila Pa 1976) 2000; 25:348–351.
66. Shen L, Fang L, Qiu Y, et al. Study on different surgical approaches for acute lumber disk protrusion combined with Cauda Equina Syndrome. Int J Clin Exp Pathol 2014; 7:8875.
67. Shi JG, Jia LS, Yuan W, et al. Clinical classification of cauda equina syndrome for proper treatment: a retrospective analysis of 39 patients. Acta Orthop 2010; 81:391–395.
68. Smith MD, Bohlman H. Spondylolisthesis treated by a single-stage operation combining decompression with in situ posterolateral and anterior fusion. An analysis of eleven patients who had long-term follow-up. J Bone Joint Surg Am 1990; 72:415–421.
69. Sokolowski MJ, Garvey TA, Perl J, et al. Postoperative lumbar epidural hematoma: does size really matter? Spine (Phila Pa 1976) 2008; 33:114–119.
70. Sun T, Liu Z, Liu S, et al. The clinical study of repairing cauda equina fibres with fibrin glue after lumbar fracture and dislocation. Spinal Cord 2010; 48:633–637.
71. Szövérfi Z, Lazary A, Bozsódi Á, et al. Primary Spinal Tumor Mortality Score (PSTMS): a novel scoring system for predicting poor survival. Spine J 2014; 14:2691–2700.
72. Takahashi T, Hanakita J, Kawaoka T, et al. Indication for partial vertebral osteotomy and realignment in posterior spinal fixation for osteoporotic thoracolumbar vertebral collapse with neurological deficits. Neurol Med Chir (Tokyo) 2016; 56:485–492.
73. Tamburrelli F, Genitiempo M, Bochicchio M, et al. Cauda equina syndrome: evaluation of the clinical outcome. Eur Rev Med Pharmacol Sci 2014; 18:1098–1105.
74. Tan G-q, He J-l, Fu B-s, et al. Lumbopelvic fixation for multiplanar sacral fractures with spinopelvic instability. Injury 2012; 43:1318–1325.
75. Todd NV. Causes and outcomes of cauda equina syndrome in medico-legal practice: a single neurosurgical experience of 40 consecutive cases. Br J Neurosurg 2011; 25:503–508.
76. Walker JL, Schulak D, Murtagh R. Midline disk herniations of the lumbar spine. South Med J 1993; 86:13–17.
77. Wostrack M, Shiban E, Obermueller T, et al. Conus medullaris and cauda equina tumors: clinical presentation, prognosis, and outcome after surgical treatment. Clinical article. J Neurosurg Spine 2014; 20:335–343.
78. Yamanishi T, Yasuda K, Yuki T, et al. Urodynamic evaluation of surgical outcome in patients with urinary retention due to central lumbar disc prolapse. Neurourol Urodyn 2003; 22:670–675.
79. Todd N, Dickson R. Standards of care in cauda equina syndrome. Br J Neurosurg 2016; 30:518–522.
80. Fraser S, Roberts L, Murphy E. Cauda equina syndrome: a literature review of its definition and clinical presentation. Arch Phys Med Rehabil 2009; 90:1964–1968.
81. Kirkham JJ, Gargon E, Clarke M, et al. Can a core outcome set improve the quality of systematic reviews? A survey of the Co-ordinating Editors of Cochrane Review Groups. Trials 2013; 14:21.
82. Tugwell P, Boers M, Brooks P, et al. OMERACT: an international initiative to improve outcome measurement in rheumatology. Trials 2007; 8:38.

cauda equina syndrome; core outcome set; neurology; neurosurgery; orthopedics; outcome domains; outcomes; Prisma; spine surgery; surgery; systematic literature review

Supplemental Digital Content

Copyright © 2018 The Author(s). Published by Wolters Kluwer Health, Inc.