Editorial. Microsurgical treatment of sacral Tarlov cysts

Ken Porche Department of Neurosurgery, University of Florida, Gainesville, Florida

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Daniel J. Hoh Department of Neurosurgery, University of Florida, Gainesville, Florida

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Chu et al. present an interesting single-institution series of a unique microsurgical approach to treat symptomatic sacral Tarlov cysts (TCs).1 Sacral TCs are extradural meningeal cysts with CSF between the endoneurium and perineurium of the nerve root sheath and contain neural tissue (nerve roots and/or dorsal root ganglia).2 While most are clinically silent without consequence, a variably reported percentage (1%–20%) may be associated with low-back or coccygeal pain, radiculopathy, paresthesia, leg weakness, bladder and bowel dysfunction, dyspareunia or sexual dysfunction, and positional headache.3 In this series, the authors report notable long-term symptomatic benefit after surgical treatment, including improved sexual dysfunction (75% of cases) and pain (93% of cases). A similar microsurgical technique was previously described in a small series by Mummaneni et al. with at least moderate improvement in radicular pain (88% of cases) and urinary incontinence (67% of cases).4

Surgical treatment of TCs is controversial, as there remains uncertainty regarding the extent of their pathologic nature, indication for surgery, surgical approach, and prognosis. Most TCs are believed to be incidental, and therefore patients with symptoms and a TC necessitate careful consideration for the possibility of another underlying spinal etiology before pursuing any invasive intervention.3 Prudent selection criteria is paramount, and variability in threshold to treat across studies may account for wide-ranging reported symptom relief with conservative versus surgical management (38%–100%).3,57

The authors list four intriguing criteria for inclusion in this surgical series. The authors indicate that all included patients had: 1) a sacral TC > 1 cm; 2) symptoms of pain or numbness in the sacral region, buttocks or lower limb, ankle weakness, and/ or bowel, bladder or sexual dysfunction; 3) failure of > 1 month of conservative management (medications and physical therapy); and 4) patient desire to undergo surgical treatment. One should note that study inclusion criteria do not necessarily equate to surgical indication, as the number of nonsurgically managed patients with one or more of these criteria is not reported.

The surgical technique involved a small sacral laminectomy at the cephalad end of the cyst, opening of the proximal cyst, and cyst occlusion with subcutaneous fat and fibrin glue. The authors make note that this technique incorporates elements of both open microsurgery (cyst fenestration and fat packing) and percutaneous interventional therapy (cyst drainage and fibrin glue injection). They present both clinical and radiological outcomes at early and long-term time points (72% at ≥ 3 years of follow-up). They describe an 87% overall symptom improvement rate at discharge and 81% rate at ≥ 3 years. Pain was the most common and effectively treated symptom, with 99% improvement at discharge and 93% at ≥ 3 years. Sexual dysfunction was the least common symptom and the least effectively treated symptom, with 75% improvement at discharge and at ≥ 3 years. Consistent with other studies, the authors report rare cyst recurrence of 5.8% on follow-up imaging. The overall complication rate was low, with a 5.7% postoperative CSF leakage rate and a 3.4% symptomatic root injury rate (which the authors attribute to minimal exposure of the intracyst nerve).

There are significant challenges in interpreting these results, particularly if considering application to general practice. The study carries inherent biases given the retrospective single-cohort, single-institution design, which may limit external validity. The authors do not report the number of sacral TC patients evaluated over the study period who did not meet inclusion criteria and/ or were simply deemed not suitable for surgery. Furthermore, the existing literature is inconsistent regarding clinical and radiological thresholds to treat. In this study, surgeons treated cysts > 1 cm while other studies have used > 1.5 cm as the cutoff.4,8,9 Delayed filling on CT myelography and pain exacerbated by postural changes or Valsalva maneuvers have been previously reported as predictors of benefit after surgery, neither of which was assessed in this study.4,10 Multiple cysts were not mentioned in the selection process, and, in these instances, it is not clear how the surgeons determined which TC to treat. Comorbid connective tissue disorders, and how they may have impacted outcome, were not discussed, unless these were excluded as "other serious comorbidities."11 Lastly, there is no standardized and validated outcome measure for sacral TCs. The authors devised their own rudimentary clinical outcomes assessment, which limits comparison with other studies.

The authors should be congratulated, however, for reporting a novel surgical approach for sacral TCs and reporting their clinical and radiological outcomes. Their video demonstrating the surgical technique is valuable. Sacral TCs remain a clear knowledge gap for the neurosurgical community with respect to pathophysiology, indication for treatment, therapeutic modality, and prognosis. Better understanding is needed to inform preoperative patient-surgeon shared decision-making and aligning expectations for postoperative outcome. This surgical series will undoubtedly serve as the basis for future investigation.

Disclosures

The authors report no conflict of interest.

References

  • 1

    Chu W, Chen X, Wen Z, et al. Microsurgical sealing for symptomatic sacral Tarlov cysts: a series of 265 cases. J Neurosurg Spine. Published online July 1, 2022. doi: 10.3171/2022.3.SPINE211437

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  • 2

    Nabors MW, Pait TG, Byrd EB, et al. Updated assessment and current classification of spinal meningeal cysts. J Neurosurg. 1988;68(3):366377.

  • 3

    Lucantoni C, Than KD, Wang AC, et al. Tarlov cysts: a controversial lesion of the sacral spine. Neurosurg Focus. 2011;31(6):E14.

  • 4

    Mummaneni PV, Pitts LH, McCormack BM, Corroo JM, Weinstein PR. Microsurgical treatment of symptomatic sacral Tarlov cysts. Neurosurgery. 2000;47(1):7479.

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  • 5

    Kunz U, Mauer UM, Waldbaur H. Lumbosacral extradural arachnoid cysts: diagnostic and indication for surgery. E Spine J. 1999;8(3):218222.

  • 6

    Jiang W, Hu Z, Hao J. Management of symptomatic Tarlov cysts: a retrospective observational study. Pain Physician. 2017;20(5):E653E660.

  • 7

    Xu J, Sun Y, Huang X, Luan W. Management of symptomatic sacral perineural cysts. PLoS One. 2012;7(6):e39958.

  • 8

    Voyadzis JM, Bhargava P, Henderson FC. Tarlov cysts: a study of 10 cases with review of the literature. J Neurosurg. 2001;95(1 suppl):2532.

  • 9

    Guo D, Shu K, Chen R, Ke C, Zhu Y, Lei T. Microsurgical treatment of symptomatic sacral perineurial cysts. Neurosurgery. 2007;60(6):10591066.

  • 10

    Neulen A, Kantelhardt SR, Pilgram-Pastor SM, Metz I, Rohde V, Giese A. Microsurgical fenestration of perineural cysts to the thecal sac at the level of the distal dural sleeve. Acta Neurochir (Wien). 2011;153(7):14271434.

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  • 11

    Arnold PM, Teuber J. Marfan syndrome and symptomatic sacral cyst: report of two cases. J Spinal Cord Med. 2013;36(5):499503.

Weihua Chu Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Xin Chen Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Zexian Wen Department of Cerebrovascular Disease, Dazhou Central Hospital, Dazhou, China

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Xingsen Xue Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Guangjian He Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Hongyan Zhang Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Jingjing Liu Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Yang Zhang Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Hua Feng Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Jiangkai Lin Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing; and

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Response

We thank Dr. Ken Porche and Dr. Daniel J. Hoh for their insightful comments on our article. Their concerns deeply reflect the current disputes and challenges in the treatment of sacral TCs.

We strongly agree that it is paramount to establish prudent and strict selection criteria for any invasive intervention for TCs. In our article, the patients who underwent microsurgical sealing met all four of the listed inclusion criteria. Additionally, we established exclusion criteria to reject patients from surgery when they only had mild pain (Numeric Rating Scale score < 3) or also presented with spinal or pelvic disorders such as spinal or pelvic tumors or trauma, lumbar disc herniation, lumbar spinal stenosis, lumbar spondylolisthesis, lumbar muscle strain, cauda equina syndrome, and pelvic inflammatory diseases. For those patients with pelvic, perineal, rectal, or urinary symptoms, specialists (gynecologists, proctologists, and urologists) were consulted to rule out relevant diseases to determine that the symptoms were indeed caused by sacral TCs. These measures in our study ensured that the TCs were the main responsible focus and established the threshold of surgical treatment.

There is no obvious corresponding relationship between TC size and symptoms.14 Cysts measuring more than 1 cm can be clearly displayed on MRI. If the symptoms of these patients are serious enough, they should be included for treatment. The fistula between a TC and the subarachnoid space originates from the nerve root sleeve, which is usually tiny and a "valve" may have formed, resulting in poor CSF flow. Therefore, CT or MR myelography shows delayed filling, which is a characteristic manifestation and exists in almost every patient with TCs.58 In our article, all the included patients were precisely diagnosed with TCs according to intraoperative confirmation. This may also be attributed to the above mechanism, the exacerbation of pain after a posture change or the Valsalva maneuver is another typical clinical sign of sacral TCs. In our series, 57.7% (153/265) of patients reported that their pain was aggravated when changing posture or performing the Valsalva maneuver. For patients with multiple cysts, unless there was clear evidence that a cyst was not related to the symptoms, we operated on all the cysts with a diameter of more than 1 cm. Considering the complexity of symptoms and the risks of surgery, patients with other comorbidities, including Marfan syndrome and Ehlers-Danlos syndrome, were excluded from this study.

The total number of sacral TC patients evaluated in our clinic over the study period (January 2003–December 2020) was 801. A total of 536 (66.9%) did not meet the inclusion criteria and were advised to receive conservative treatment. We conducted a clinical trial (identifier no. NCT02595190, ClinicalTrials.gov) to compare the long-term effects between adhering to conservative treatment and choosing surgical treatment. Unfortunately, due to the compliance and high loss of follow-up of the patients with conservative treatment, we were not able to complete the study.

There are some deficiencies in our article. Although we established a series of criteria, the stratification of outcomes in this study was nonstandardized. Of course, there remains a lack of standardized and validated outcome measures for the treatment of sacral TCs. More advanced clinical outcome measures, such as prognostic scoring systems, should be adopted in future research. The study was a single-center retrospective analysis, and the data collected were limited, so it is difficult to avoid confusion and selection bias. A multicenter, prospective, randomized controlled trial is necessary to compare microsurgical sealing with other surgical techniques or percutaneous interventions.

References

  • 1

    Langdown AJ, Grundy JRB, Birch NC. The clinical relevance of Tarlov cysts. J Spinal Disord Tech. 2005;18(1):2933.

  • 2

    Lim VM, Khanna R, Kalinkin O, Castellanos ME, Hibner M. Evaluating the discordant relationship between Tarlov cysts and symptoms of pudendal neuralgia. Am J Obstet Gynecol. 2020;222(1):70.e7170.e76.

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    • Search Google Scholar
    • Export Citation
  • 3

    Murphy K, Oaklander AL, Elias G, Kathuria S, Long DM. Treatment of 213 patients with symptomatic Tarlov cysts by CT-guided percutaneous injection of fibrin sealant. AJNR Am J Neuroradiol. 2016;37(2):373379.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Burke JF, Thawani JP, Berger I, et al. Microsurgical treatment of sacral perineural (Tarlov) cysts: case series and review of the literature. J Neurosurg Spine. 2016;24(5):700707.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Kikuchi M, Takai K, Isoo A, Taniguchi M. Myelographic CT, a check-valve mechanism, and microsurgical treatment of sacral perineural Tarlov cysts. World Neurosurg. 2020;136:e322e327.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Tanaka M, Nakahara S, Ito Y, et al. Surgical results of sacral perineural (Tarlov) cysts. Acta Med Okayama. 2006;60(1):6570.

  • 7

    Voyadzis JM, Bhargava P, Henderson FC. Tarlov cysts: a study of 10 cases with review of the literature. J Neurosurg. 2001;95(1 suppl):2532.

  • 8

    Fletcher-Sandersjöö A, Mirza S, Burström G, et al. Management of perineural (Tarlov) cysts: a population-based cohort study and algorithm for the selection of surgical candidates. Acta Neurochir (Wien). 2019;161(9):19091915.

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Illustrations from Hagan et al. (pp 843–850). © Albert Telfeian, published with permission.

  • 1

    Chu W, Chen X, Wen Z, et al. Microsurgical sealing for symptomatic sacral Tarlov cysts: a series of 265 cases. J Neurosurg Spine. Published online July 1, 2022. doi: 10.3171/2022.3.SPINE211437

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Nabors MW, Pait TG, Byrd EB, et al. Updated assessment and current classification of spinal meningeal cysts. J Neurosurg. 1988;68(3):366377.

  • 3

    Lucantoni C, Than KD, Wang AC, et al. Tarlov cysts: a controversial lesion of the sacral spine. Neurosurg Focus. 2011;31(6):E14.

  • 4

    Mummaneni PV, Pitts LH, McCormack BM, Corroo JM, Weinstein PR. Microsurgical treatment of symptomatic sacral Tarlov cysts. Neurosurgery. 2000;47(1):7479.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Kunz U, Mauer UM, Waldbaur H. Lumbosacral extradural arachnoid cysts: diagnostic and indication for surgery. E Spine J. 1999;8(3):218222.

  • 6

    Jiang W, Hu Z, Hao J. Management of symptomatic Tarlov cysts: a retrospective observational study. Pain Physician. 2017;20(5):E653E660.

  • 7

    Xu J, Sun Y, Huang X, Luan W. Management of symptomatic sacral perineural cysts. PLoS One. 2012;7(6):e39958.

  • 8

    Voyadzis JM, Bhargava P, Henderson FC. Tarlov cysts: a study of 10 cases with review of the literature. J Neurosurg. 2001;95(1 suppl):2532.

  • 9

    Guo D, Shu K, Chen R, Ke C, Zhu Y, Lei T. Microsurgical treatment of symptomatic sacral perineurial cysts. Neurosurgery. 2007;60(6):10591066.

  • 10

    Neulen A, Kantelhardt SR, Pilgram-Pastor SM, Metz I, Rohde V, Giese A. Microsurgical fenestration of perineural cysts to the thecal sac at the level of the distal dural sleeve. Acta Neurochir (Wien). 2011;153(7):14271434.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Arnold PM, Teuber J. Marfan syndrome and symptomatic sacral cyst: report of two cases. J Spinal Cord Med. 2013;36(5):499503.

  • 1

    Langdown AJ, Grundy JRB, Birch NC. The clinical relevance of Tarlov cysts. J Spinal Disord Tech. 2005;18(1):2933.

  • 2

    Lim VM, Khanna R, Kalinkin O, Castellanos ME, Hibner M. Evaluating the discordant relationship between Tarlov cysts and symptoms of pudendal neuralgia. Am J Obstet Gynecol. 2020;222(1):70.e7170.e76.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Murphy K, Oaklander AL, Elias G, Kathuria S, Long DM. Treatment of 213 patients with symptomatic Tarlov cysts by CT-guided percutaneous injection of fibrin sealant. AJNR Am J Neuroradiol. 2016;37(2):373379.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Burke JF, Thawani JP, Berger I, et al. Microsurgical treatment of sacral perineural (Tarlov) cysts: case series and review of the literature. J Neurosurg Spine. 2016;24(5):700707.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Kikuchi M, Takai K, Isoo A, Taniguchi M. Myelographic CT, a check-valve mechanism, and microsurgical treatment of sacral perineural Tarlov cysts. World Neurosurg. 2020;136:e322e327.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Tanaka M, Nakahara S, Ito Y, et al. Surgical results of sacral perineural (Tarlov) cysts. Acta Med Okayama. 2006;60(1):6570.

  • 7

    Voyadzis JM, Bhargava P, Henderson FC. Tarlov cysts: a study of 10 cases with review of the literature. J Neurosurg. 2001;95(1 suppl):2532.

  • 8

    Fletcher-Sandersjöö A, Mirza S, Burström G, et al. Management of perineural (Tarlov) cysts: a population-based cohort study and algorithm for the selection of surgical candidates. Acta Neurochir (Wien). 2019;161(9):19091915.

    • PubMed
    • Search Google Scholar
    • Export Citation

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