Abstract
Spondylolysis is increasingly associated with specific sports, timely and effective management of which underpins successful return to sports. Hence, the main purpose of this systematic review of reviews [RoR] is to summarize data from published reviews exploring the return to play in athletes with spondylolysis managed conservatively or surgically, thereby providing for recommendations for future practice and research.
A systematic review of review of articles published in English and since 2015 was conducted online using PubMed and Google Scholar, as per Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines. Predefined eligibility criteria were applied, and the data thus compiled were analyzed. Study quality was assessed using the AMSTAR-2 checklist.
A total of 7 systematic reviews and meta-analysis consisting of 51 primary studies were included in the review. The result of this RoR highlights the knowledge gap and limitations in RTP research post spondylolysis with existing heterogeneity in methods and reporting amid other factors within primary studies. Further quality of the study was found to be of low to critically low confidence based on the AMSTAR-2 scale, suggesting that the results should be interpreted with great caution.
Though both conservative and surgical approaches increase the percentage of athletes returning to play, the evidence remains largely limited and inconclusive as to which is better. However, it appears that surgical interventions give those who failed a trial of conservative approach, a better shot at return to play. There is a need for further high-quality, appropriately powered, well-designed, multicentered studies, and also for consensus regarding “returning to play” definition and outcome measures.
Keywords: Spondylolysis, Pars interarticularis, Return to play, Return to sports
Introduction
Spondylolysis has been consistently reported across sports, with an increasing number reported in sports like diving, cricket, baseball, rugby, weight-lifting, wrestling, and gymnastics.1,2 The pathomechanics in sports has been attributed to repetitive spinal hyperextension and rotation with loading.2 Untreated, they run a risk of progressing to spondylolisthesis and long-term neural complications, apart from proving to be career-changing or ending.3, 4, 5, 6, 7 Hence, timely and appropriate management underpins successful and early return to play [RTP] or sports [RTS]. Though there isn't a gold standard approach in managing spondylolysis, conservative management (braces, activity modification, physical therapy modalities, and exercises) is most widely used. Surgical management with a bouquet of approaches is reserved for those who fail conservative management usually over 6 months or fail to return to sports or lack true healing.5,8 Hence, the main purpose of this review was to summarize data from published reviews exploring RTP in athletes with spondylolysis managed conservatively or surgically, thereby providing for recommendations for future practice and research. A systematic review of systematic reviews and meta-analysis [RoR] approach was opted to comprehensively synthesize and summarize the evidence in regards to RTP post spondylolysis.
Methodology
Computerized literature searches, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Fig. 1),9 were performed for review and meta-analysis of articles published in English since 2015 using PubMed and Google Scholar, to synthesize current evidence. The following keywords were used: spondylolysis and pars interarticularis, in combination with review, and meta-analysis in title, and publication type with publication date since January 2015 as filter. The bibliographies of all located articles and a forward citation search were also performed. The search was completed by 20 July 2020. Ethical approval was not obtained as the study essentially was a review of previously published works. Prior defined but unpublished protocol was followed.
Fig. 1.
Study selection—PRISMA guidelines.
Scientific merit assessment—methodological quality
The scientific merit assessment was applied as an analytical instrument and wasn't a criterion for study exclusion. Study quality was assessed, by a single reviewer, using the A MeaSurement Tool to Assess systematic Reviews-2 (AMSTAR-2) tool,10 a 16-item checklist with four possible responses: yes, partial yes, no, or not applicable. Of the 16 items, 7 are considered “critical” domains. The reviews were rated to be of high, moderate, low, or critically low overall confidence as suggested by the tool guideline.10
Study eligibility
Studies were considered eligible if they fulfilled the following criteria: were systematic reviews and/or meta-analysis published in English and with full-text availability, were systematic reviews reporting RTP or RTS post spondylolysis management, and were reviews published in or after 2015.
Studies were excluded if they adhered to any of the following exclusion criteria: reviews reporting on epidemiology, pathomechanics, or clinical and imaging outcomes; studies other than systematic reviews (narrative/general reviews, abstracts, case reports/series, thesis, letters, conference papers, book chapters, unpublished works, and commentaries); and duplicate publications.
Data extraction and synthesis
Screening of all eligible publications was carried out by a single reviewer for titles, abstracts, full text, and bibliographies, utilizing predetermined criteria. In the case of multiple versions of reviews, the most current version was included, and in the case of multiple publications of identical reviews, the most detailed publication was included.
Data were extracted by a single reviewer from the reports and are summarized descriptively with the help of tables and graphs. In case of any missing data, no attempt was made to contact the corresponding author.
Results
Of the 10 eligible studies, 6 reviews1,11,13, 14, 15, 16 were included in the present RoR. Additionally one study12 was included based on supplementary search/suggestion, making the total number of included studies as 7. The characteristics and findings of the included reviews are summarized in Table 1, Table 2, Table 3. One review though was published under the title narrative review,15 it was included in the present RoR because the authors used a systematic approach and calculated the weighted mean for RTP. The reviews included 51 primary studies, with 5.88% of primary studies included in five reviews, 3.92% in four reviews, 11.76% in three reviews, and 19.61% in two reviews.
Table 1.
Summary of reviews included in the overview.
| Study | Article type | Objective | Articles included | Study Type | Database searched | Search period | Language restriction | Guidelines | Quality assessment |
|---|---|---|---|---|---|---|---|---|---|
| Tawfik et al., 2020 1 | SR | Incidence of Pars Interarticularis Defects in Athletes | 5 | Case series | 6 | Inception to September 2017 | English | NR | NR |
| Grazina et al., 2019 11 | SR | Conservative vs. surgical | 14 [8 conservative, 7 surgical] | Level IV | 3 | Inception to May 31, 2017 | English | PRISMA | OCEBM Joanna Briggs Institute Checklist for Case Series tool Risk of bias assessment |
| Sellyn et al., 2019 12 | SR | Postsurgical return to play | 15 | Level III & IV | 1 | Inception to May 2018 | English | PRISMA | Level 1 to 5 |
| Overley et al., 2018 13 | MA | Conservative vs. surgical | 11 [7 conservative, 4 surgical] | NR | 3 | January 1990 to December 2014 | English | PRISMA | Modified Downs and Black checklist |
| Kolcun et al., 2017 14., | SR | Minimally invasive versus conventional repair | 16 [8—MIS, 8—CDR] | Case series, Case reports | 1 | Inception to April 2016 | English | PRISMA | North American Spine Society standards |
| Panteliadis et al., 2016 15 | SR | Conservative vs. surgical | 25 [ 11 conservative, 15 surgical] | Level IV or Level V | 1 | NR | English | NR | EBM |
| Scheepers et al., 2015 16 | SR | Conservative vs. surgical—unilateral spondylolysis | 5 | Quasi-experimental and case series | 14 | 1 January 1970 and 1 September 2013 | English | JBI | JBI-MAStARI |
CDR – Conventional Direct Repair, EBM – Evidence Based Medicine approach, JBI - Joanna Briggs Institute, JBI-MAStARI - Joanna Briggs Institute's Meta-Analysis of Statistics Assessment and Review Instrument for appraising observational studies, MA – Meta-Analysis, MIS – Minimally Invasive Surgery, NR – Not Reported, OCEBM - Oxford Centre of Evidence-Based Medicine, PRISMA - Preferred Reporting Items for Systematic Reviews and Meta-Analyses, SR – Systematic Review.
Table 2.
Summary of studies within each review included in the overview.
| Sample size | Age (years) | Male [%] | Lumbar level [%] | Sports | Sporting level | Mean Follow-up period [months] | ||
|---|---|---|---|---|---|---|---|---|
| Grazina et al., 2019 11 | Overall | 592 | 7–37 (range) | 59 | L4 = 12.4 L5 = 78.6 |
Multiple | Heterogeneous | – |
| Conservative | 492 | 7–60 (range) | 59–100 | L5 = 55–88.5 L4 = 10.6–36 L3 = 1.9–17.1 L4+L5 = 3.6–9 L2 = 1–3.6 Multi = 6.1–9.2 |
Multiple | Heterogeneous | 13.2–50.4 | |
| Surgery | 100 | 10–37 [6 studies] | 33.3–100 | L5 = 68.2–90 L4 = 6.5–28.6 L3 = 6.5–71.4 L4/L5 = 4.5–5 Multi = 3.2 |
Multiple | Competitive, collegiate, professional, high school | 11.9–78 | |
| Sellyn et al., 2019 12 | Surgery | 3 to 34 | 9–48 (range) | – | – | Multiple | – | – |
| Overley et al., 2018 13 | Overall | 376 | – | – | – | Multiple | – | 13.2–68 |
| Conservative | 245 | 7–31 (range) | – | – | – | – | 29 | |
| Surgery | 74 | 13–37 (range) | – | – | – | – | 38.4 | |
| Kolcun et al., 2017 14 | Overall | 150 | – | – | – | – | – | – |
| Surgery [MIS] | 46 | 32.9 (mean) | 72 | L5 = 83 L4 = 13 L3 = 2.9 Bilateral = 89 |
Football, hockey, track, volleyball | Professional, college, high school | 12.7 | |
| Surgery [CDR] | 104 | 23.1 (mean) | 57 | L5 = 83 L4 = 11 L3 = 5 L2 = 1.2 Bilateral = 80% |
Multiple | College, professional, amateur | 44.8 | |
| Panteliadis et al., 2016 15 | Conservative | 390 | 16.2 (mean) | 53.59 | L5 = 85.13 Bilateral = 76.4 |
Multiple | – | 45.3 |
| Surgical | 174 | 22.3 (mean) | 67.24 | – | Multiple | – | 52 | |
| Scheepers et al., 2015 16 | Overall | 113a | 10–35 (range) | 83 | Unilateral = 62.83 | Multiple | Professional & amateur | 6 months to 10 years |
CDR—Conventional Direct Repair, MIS—Minimally Invasive Surgery.
Of the 113, 104 were athletes.
Table 3.
Summary of return to play findings across reviews.
| Study | RTP measure | Overall | Surgery | Conservative |
|---|---|---|---|---|
| Tawfik et al., 2020 1 | RTP to previous level [%] | 82.43a | – | – |
| Grazina et al., 2019 11 | RTP at any level [% (range)] | 92 (68–100) | 88 (71–100) | 92 (68–97) |
| RTP at pre-injury level [% (range)] | 88 (68–100) | 81 (70–100) | 89 (68–97) | |
| Time to RTP [months (range)] | 4.6 | 6.4 (6–7) | 4.3 (2–5.5) | |
| Sellyn et al., 2019 12 | RTP [%] | – | 61–100 | – |
| Time to RTP [months (range)] | – | 3–26 | – | |
| Overley et al., 2018 13b | Average time to RTP [months] | 2 to 7.3 | 6.5 | 5.9 |
| RTP (%) | – | 90.3 | 92.2 | |
| Kolcun et al., 2017 14 | Average time to RTP [months (range)] | – | MIS = 2.7 (0.75–6.0) CDR = 5.6 (4–6) |
– |
| RTP to previous activity level [%] | – | MIS = 95.65 CDR = 97.11 |
– | |
| Panteliadis et al 2016 15 | RTP [months] | – | 7.9 | 3.7 |
| Scheeper et al., 2015 16 | RTS at 6 months [%] | – | Overall = 86 Unilateral = 79 |
Overall = 98 |
RTP— return to play, RTS—return to sports.
8.11% retired.
Statistically no heterogeneity reported in conservative arm while mild heterogeneity was reported in surgical arm.
A meta-analysis of RoR is a challenging task owing to the review heterogeneity, methodological variability, and overlap of primary studies within the systematic review included. Hence a narrative approach was used in the current review.
Scientific merit assessment of included reviews
Of the seven reviews, five1,12, 13, 14, 15 received critically low confidence appraisals based on AMSTAR-2 assessment, exhibiting more than one critical flaw (Fig. 2), while two reviews11,16 received low confidence appraisal exhibiting one critical flaw.
Fig. 2.
Distribution summary of reviews across AMSTAR-2 criteria.
Scientific merit assessment within reviews
Various quality assessment tools were used across reviews [Table 1] to assess the quality of studies and level of evidence. The studies were mostly of moderate quality11,13,16 and were level IV.1,11,12 But then, the studies within reviews were subjected to numerous flaws11,16 like lack of appropriate follow-up, blinding, randomization, control, standard outcome measures, and statistical analysis, with inconsistency in recruitment and methodology. The studies were further subjected to selection bias, assessor bias, and attrition bias.11
Return to play
The RTP findings reported across reviews are summarized in Table 3. There was a lack of a standard RTP definition with inconsistencies in reporting across studies within reviews. RTP was expressed variedly as mean percentage of return to any level, return to pre-injury level, returning to sport and logging regular season playing time in at least one game, or time to RTS (months) across reviews. Further, RTP criteria were lacking, inconsistent, or unclear across studies within reviews. Of those reporting the criteria, they were reported to be subjective, symptom-based, time-based, or imaging-based.
Mean duration of symptoms
Reporting of the mean duration of symptoms was grossly lacking, with only one review reporting the same based on 43%–50% of primary studies reporting the same.11 It was reported to range from 2.8 to 4.5 months in the conservative group and from 9.4 to 26.4 months in the surgical group.
Injury diagnosis
Of the seven reviews, four13−16 included radiologically diagnosed spondylolysis patients in their review, while one review11 reported the use of standardized, reliable, and valid diagnostic methods by 78.57% of the primary studies. The imaging modalities used included high resolution computed tomography [CT] scan, magnetic resonance imaging [MRI], or single-photon emission computed tomography [SPECT].
Vertebral level
L5 was the most common level found to be involved across reviews [Table 2]..
Sports and level of participation
The information regarding sports and the level of participation are summarized in Table 2. Athletes belonged to multiple sports across all reviews. But the most common sports, of those reporting it, included cricket,16 football,11,15 soccer,11,15 and baseball.11 Information regarding the level of participation was inconsistent or lacking.
Management approaches
Heterogeneous management approaches were reported across reviews. With a conservative approach including a varied mix of the following—modification or restriction of sports participation, bracing [Thoracolumbosacral orthoses (TLSO), Lumbosacral Orthosis (LSO), and/or nonrigid braces], physical therapy exercises and modalities, and bone growth stimulation.11,13,15,16 Among braces, TLSO brace was reported to be more commonly used than LSO brace in one review,15 with an average return to play time of 5.6 months and 5.4 months with TLSO and LSO brace use, respectively, based on very limited information.
Similarly, varied surgical approaches were mentioned across reviews.11, 12, 13, 14, 15, 16 The approaches included bone grafting techniques [iliac crest, spinous process], direct surgical repair using screw or wire fixation, or micro-invasive surgery. The most common technique reported across reviews was the Bucks technique or its modification12,14,15 ranging from 52% to 75%. Further, though only one review14 comparing micro-invasive approach to conventional approach reported on average operative time, blood loss, and hospital stay, the effect of the same on RTP wasn't explored owing to inconsistent reporting across primary studies.
Surgical indications
The most common indication for surgery was failed conservative management with the inability to return to activity across reviews.11,13, 14, 15, 16 The time frame to resort to surgical approach varied grossly across primary studies within reviews ranging from 3 months to 60 months.
Postoperative management
Postoperative care was reported only across one review,11 which varied grossly between individual studies with activity limitation and rehabilitation ranging from 4–6 weeks to 6 months.
Surgical complications
Of the limited studies reporting on surgical complications across the review, the overall surgical complication rate ranged from 2.89% to 34%.11,13, 14, 15 The various complications reported include superficial wound infection, nonunion, hardware associated (breakage, pull-out), transverse process fracture, degeneration, and recurrence. One review reported the compression screw to have a statistically lower risk of complications15 in comparison to segmental wire fixation [6.56% vs. 16.22%, respectively], while one other review reported lower complication rate with the conventional approach in comparison to micro-invasive approach [2.89% vs. 4.35%, respectively].14
Country of study
Only one review reported on the geographical location of the study16 with all studies being performed in developed countries with well-established healthcare systems.
Associate injuries/Comorbidities
Data on associated injuries or comorbidities were lacking across all reviews, owing to lack of reporting in primary studies per se.11,16
Miscellaneous
Treatment duration and union rates were reported only in one review15 based on limited data within primary studies.
Study limitations
Various limitations of primary studies were reported across reviews1,11, 12, 13, 14, 15, 16 and these include low powered studies, study characteristics (mostly descriptive, retrospective, and level IV studies), inconsistent methodology (lack of follow-up, control, randomization, blinding, comparative analysis, recovery confirmation, recruitment, and selection bias), lack of appropriate statistical analysis and inability to carry out a meta-analysis, and heterogeneous study characteristics (clinical metrics, sample characteristics, surgical indication and approach, conservative approach, and imaging modalities). Further, there was a lack of consensus on factors like “return to play” definition and performance-based outcome measures.
Limitations and lack of reporting within primary studies rendered reviews unable to perform further analysis of the effect of various other important factors on RTP like age,11 gender,16 pre-injury participation level,11,12 defect (single vs. multiple),1 different surgical approaches,13 lumbar level involvement,13 laterality (unilateral vs. bilateral),13 sporting level,12,15,16 and quality of performance following return.16
Discussion
The current RoR was undertaken with the main objective of summarizing data from published reviews exploring RTP post spondylolysis management, thereby providing for recommendations for future practice and research. Seven reviews were identified with a total of 51 primary studies. Reviews were published every year over the study period denoting a constant interest in the topic. The result of this RoR highlights the knowledge gap and limitations in RTP research post spondylolysis with existing heterogeneity in methods and reporting amidst other factors within primary studies. Further quality of the study was found to be of low to critically low confidence based on the AMSTAR-2 scale, suggesting that the results should be interpreted with great caution.
Based on the limited evidence, the overall RTP to any level ranged from 61% to 100%, while 82% returned to pre-injury level [Table 3]. The RTP percentage and time was also similar [Table 3]. However, the results are to be approached with caution owing to the various limitations outlined before. The evidence comparing conservative approach to surgical approach is inconclusive, as the studies were all subjected to selection bias with the surgical group involving those who failed conservative approach, which means that the RTP time reported in the surgical group includes time spent in conservative management plus the time since surgery to play. Further factors that may be involved in the failure of conservative trials like compliance and player motivation or willingness to RTP early demanding aggressive approach weren't considered.
Though there seems to be a trend toward better outcome and increase in the RTP with both conservative and direct surgical approaches—effect of various influences remains unclear—role and effect of brace (recovery enhancer or just a resting tool), the timing of surgery, surgical approach and technique, surgeons characteristics, per-operative factors [duration of surgery, blood loss, length of hospital stay], and postoperative factors [activity restriction duration, time in the brace, rehabilitation approaches including frequency]. Further, RTP postoperatively has been reported to be influenced by surgeon's preference with some advocating graded return, some return to contact sports at 1 year, and some advising against the return to contact sports altogether,5,6 and specificity of sport with dance, gymnastics, and wrestling deemed to be career-changing or ending as they involve extreme ranges of motion or heavy loading.5, 6, 7
Additionally, though surgical management is known to carry the risk of postoperative complications, data regarding the same, and that exploring the effect of the same on RTP was grossly lacking across reviews. Of those reporting postop complications, it ranged from 2.89% to 34%,11,13, 14, 15 demanding the need to weigh risk against benefit while considering surgical management. However, based on the available evidence, the surgical approach seems to be beneficial in those who failed a conservative approach for returning to sport.
The present RoR highlights gross limitation in research on the effect of various factors on RTP like—gender, lumbar level, sport specificity, sporting level, anthropometric measures [weight, height, and BMI], spinal alignment, and timing of injury/diagnosis (in season or off-season). This is significant as various risk factors have been associated with spondylolysis like male sex, race, family history, increase lumbar lordosis, high body mass index, and specific sports like dance or cricket,1,17, 18, 19 with L5 being the common vertebral level involved, and often bilaterally.1,20 Further, as surgical management of spondylolysis can be career-ending,5, 6, 7 the level and quality of RTS remain unclear.
Further, there was a lack of information on RTP definition, recovery confirmation, stage or grading of lesions, associated injuries, standardized clinical metrics, and performance outcome measures. Additionally, few other factors weren't considered within the reviews, which may also affect the outcomes, like details of assessor/surgeon and country of study, which may add to approach and protocol variability.
The present RoR is not without limitations. The reviews included were subjected to heterogeneity per se and due to the primary studies involved, owing to varied study objectives, diverse methodology, heterogeneous study population and setting, varied study designs, varied RTP measures, lack of standardized RTP criteria, lack of standard performance-based outcome measure, lack of appropriate follow-up, and inconsistent reporting. The current RoR was single reviewer based and involved two databases, thereby raising the possibility of reviews being missed despite a comprehensive search. Additionally, a meta-analysis couldn't be performed owing to study and data heterogeneity across the reviews. This RoR might be subjected to publication bias, as it was limited to reviews published and in the English language. Due to the above limitations and also those outlined by individual reviews, great caution is needed to be exercised while interpreting results published across various reviews.
The result of this RoR highlights the existing gap and limitations in the RTP research post spondylolysis with existing heterogeneity in methods and reporting amid other factors. However, the RoR finding does indicate the role of surgical management in increasing RTP chances in those athletes who failed conservative management. The RoR also stresses on the need for consensus in regards to RTP definition, clinical metrics, and performance-based outcome measures.
Way forward
Appropriately powered research employing multicentred, sport-specific, randomized control trial or a longitudinal study design with an appropriate follow-up period, with adherence to standard reporting guidelines, and with rigorous statistical analysis is required. There is a need for consensus and standardization in regards to RTP definition, management pathway, and outcome measures [clinical, imaging, and performance based] ensuring comparability. The research needs to take into account various factors like below,
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Assessment characteristics (assessor characteristics, RTP definition and criteria, and outcome measures),
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Athlete characteristics (age, sex, height, weight, BMI, associated injuries, previous injuries, treatment compliance, and motive),
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Sporting characteristics (the type of sport and level of participation)
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Injury characteristics (laterality—unilateral or bilateral and timing of injury—in-season or off-season)
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Management approach (conservative vs. surgical)
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Surgical characteristics (type and approach, and surgeon characteristics),
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Geographical characteristics (country of study—as protocols and approaches may differ),
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Rehabilitation/sport-specific training protocols.
Conclusions
Injuries in athletes may prove career-changing or career-ending, thereby demanding an appropriately timed evidence-backed management pathway ensuring complete and speedy recovery with return to sports at a competitive level without any compromise in career and preventing recurrence and any complications. Though both conservative and surgical approach increases the percentage of athletes returning to play, the evidence remains largely limited and inconclusive as to which is better. However, it appears that surgical interventions give those who failed a trial of conservative approach, a better shot at return to play. There is a need for further high-quality, appropriately powered, well-designed multicentered studies, and also for consensus in regards to “return to play” definition and outcome measures.
Disclosure of competing interest
The authors have none to declare.
Footnotes
Supplementary data to this article can be found online at https://doi.org/10.1016/j.mjafi.2020.11.011.
Appendix A. Supplementary data
The following is the Supplementary data to this article:
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