Clinical and radiological features of spinal extradural arachnoid cysts: Valve-like mechanism involving the nerve root fiber as a possible cause of cyst expansion

Expanding the Horizons of Minimally Invasive Spine Surgery: Experience of the Destandau Technique for the Treatment of Multiple Spinal Diseases

OBJECTIVE

Minimally invasive spine surgery is rapidly gaining popularity because of its versatile nature. Traditionally, prolapsed disc has been the most common disease targeted using this technique. However, its usefulness for various other diseases has also been shown in studies. We present our experience of using this technique for various spinal diseases apart from prolapsed discs.

METHODS

This is a retrospective study in which patients operated on by a single surgeon from January 2019 to April 2023 were included. Cases that required conversion to open technique were excluded. Intraoperative findings and postoperative courses were obtained from patient records.

RESULTS

A total of 47 patients were included in the study, of whom 29 were male and 18 were female. The various diseases treated comprised intradural extramedullary (IDEM) tumors (n = 23), hypertrophied/ossified ligamentum flavum (n = 9), arachnoid cysts (n = 6), dermoid/epidermoid cysts (n = 4), detethering of cord (n = 3), and posterior cervical decompression for an ossified posterior longitudinal ligament (n = 2). The average duration of surgery was 2.1 ± 1.2 hours and the mean intraoperative blood loss was 138.4 ± 59.1 mL. The mean length of hospital stay was 2.3 ± 0.9 days. Two patients had superficial wound infection and none of the operated patients had cerebrospinal fluid leakage. Re-exploration was not required in any of the operated patients.

CONCLUSIONS

Minimally invasive techniques for dealing with multiple diseases involving the spine are as good as traditional open techniques, with some additional advantages of lesser tissue trauma, early return to work, and so on. However, one must overcome the steep learning curve before adopting them in day-to-day practice.

How to locate the fistula orifice of spinal extradural arachnoid cyst: Surgical experience and clinical outcome

BACKGROUND

In clinical practice, spinal extradural arachnoid cysts (SEAC) are relatively rare. The key to the treatment of SEAC is recognize and close the dural defects (fistula orifice), but there is currently no convenient method to locate and identify the fistula. We propose a method for predicting the location of lumbar/thoracolumbar SEAC fistula based on surgical experience, subsequently closing the fistula through posterior unilateral interlaminar fenestration. Evaluating its surgical efficacy and investigated its effect on patient prognosis.

METHODS

A stepped approach based on clinical experience is proposed. A retrospective analysis was performed on 6 patients diagnosed with thoracolumbar SEAC disease and treated with posterior unilateral interlaminar fenestration through the position by pre-estimated fistula orifice in our hospital's Department of Neurosurgery between January 2017 and January 2022.

RESULTS

All patients who received this treatment experienced significantly lower postoperative VAS pain scores and ODI index compared to their corresponding preoperative values (P < 0.01). During the ongoing follow-up after surgery, no unstable vertebral column, adverse effects, or complications were reported.

CONCLUSIONS

The use of posterior unilateral interlaminar fenestration for the treatment of large SEAC in the adult lumbar/thoracolumbar segment can reduce spinal cord manipulation and enhance spine stability. The disease can be treated by sealing the fistula orifice through a small fenestra, the position of which is assessed before surgery. This surgical method reduces trauma and improves the prognosis of patients with large SEAC.

Spinal extradural arachnoid cysts: A novel formation mechanism and dural defect location technology

Purpose

The formation mechanism of spinal extradural arachnoid cysts (SEACs) remains unclear. There are several hypotheses for the formation of SEACs, but none of them can fully explain its pathological findings and surgical procedures. In this study, we retrospectively analyzed the cases of SEACs, aiming to clarify the formation mechanism of SEACs. In addition, we summarize a concise method for locating dural defects preoperatively and formulate a putative explanation of this method.

Methods

The clinical data of 14 patients with SEACs underwent surgery in our hospital from January 2017 to December 2021 were retrospectively analyzed.

Results

Fourteen patients were identified during the study period. The cysts all spanned the T12/L1 segment, and dural defects were also located at the T12/L1 level (2 cases not recorded) as well as the middle or the upper-middle level of the cysts. Nine cases were treated with total cyst excision, 2 cases were treated with dural defect closure only, and 3 cases were treated with total cyst excision and dural defect closure. Histopathological examination demonstrated that the cyst wall contained both the arachnoid epithelial and compact fibrous connective tissue. The symptoms were relieved in all patients, and no recurrence was observed.

Conclusions

According to intraoperative and pathological findings, the dural outer layer cyst (DOLC) is a more reasonable hypothesis about SEACs formation. When CT myelography or cinematic MRI cannot determine the location of the dural defect preoperatively, it can be located according to the middle level of the SEACs with high accuracy.

How to locate the dural defect in a spinal extradural meningeal cyst: a literature review

Spinal extradural meningeal cysts (SEMCs) are rare lesions of the spinal canal. Although closure of the dural defect can achieve satisfactory therapeutic effects, locating the fistula is difficult. This review summarizes the methods for locating the fistula of SEMCs and the distribution and features of fistula sites.

This was a non-systematic literature review of studies on SEMCs. We searched PubMed for English-language articles to summarize the methods of locating the defect. The search words were “epidural arachnoid cyst,” “dural cyst,” “epidural cyst,” and “epidural meningeal cyst.” For the defect location component of the study, case reports, studies with a sample size less than four, controversial ventral dural dissection(s), and undocumented fistula location reports were excluded.

Our review showed that radiography and computed tomography (CT) may show changes in the bony structure of the spine, with the largest segment of change indicating the fistula site. Occasionally, magnetic resonance imaging (MRI) can show a cerebrospinal fluid (CSF) flow void at the fistula site. The middle segment of the cyst on sagittal MRI, the largest cyst area, and cyst laterality in the axial view indicate the fistula location. Myelography can show the fistula location in the area of the enhanced cyst and subarachnoid stenosis. Digital subtraction or delayed CT can be used to observe the location of the initial cyst filling. Cine MRI and time-spatial labeling inversion pulse techniques can be used to observe CSF flow. Steady-state image construction interference sequence MRI has a high spatial resolution. Neuroendoscopy, MRI myelography, and ultrasound fistula detection can be performed intraoperatively. Moreover, the fistula was located most often in the T12–L1 segment.

Identifying the fistula location is difficult and requires a combination of multiple examinations and experience for comprehensive judgment.

Impact of Surgical Timing on Neurological Outcomes for Spinal Arachnoid Cyst: A Single Institution Series

Objective

Spinal arachnoid cysts (SACs) are rare lesions that often present with back pain and myelopathy. There is a paucity of literature evaluating the impact of surgical timing on neurological outcomes for primary SAC management. To compare long-term neurological outcomes in patients who were managed differently and to understand natural progression of SAC.

Methods

We conducted a retrospective analysis of adult patients treated for SAC at our institution from 2010 to 2021, stratified into 3 groups (conservative management only, surgical management, or conservative followed by surgical management). Study outcome measures were neurological outcomes as measured by modified McCormick Neurologic Scale (MNS), postoperative complications, and cyst recurrence. Nonparametric analysis was performed to evaluate differences between groups for selected endpoints.

Results

Thirty-six patients with SAC were identified. Eighteen patients were managed surgically. The remaining 18 patients were managed conservatively with outpatient serial imaging, 7 of whom (38.9%) ultimately underwent surgical treatment due to neurological decline. Most common presenting symptoms included back pain (50.0%), extremity weakness (36.1%), and numbness/paresthesia (36.1%). Initial/preoperative (p = 0.017) and 1-year postoperative (p = 0.006) MNS were significantly different between the 3 groups, but not at 6 weeks or 6 months postoperatively (p > 0.05). Additionally, at 1 year, there was no difference in MNS between patients managed surgically and those managed conservatively but ultimately underwent surgery (p > 0.99).

Conclusion

Delayed surgical intervention in minimally symptomatic patients does not seem to result in worse long-term neurofunctional outcomes. At 1 year, postoperative MNS were significantly higher in both surgical groups, when compared to the conservative group highlighting worsening clinical picture regardless of preoperative observational status.

Clinical Profile and Treatment Outcome of Spinal Epidural Arachnoid Cysts: A Systematic Review of Case Studies and Reports

Background A spinal epidural arachnoid cyst (SEAC) is a rare clinical entity. We performed a systematic review of the literature to obtain information regarding demographics, clinical presentation, treatment modalities, and outcome of SEACs.

Methods A literature search was performed by using the databases PubMed/Medline, PubMed Central, Embase, Cochrane Library, Ovid MEDLINE, and Ovid Medline In-Process. A total of 170 articles were found on literature search. We found 575 cases of SEAC since 1904 for inclusion in the review including three cases which were operated by us. We studied the patient characteristics, clinical features, and management strategies, and evaluated their outcome.

Results The average age of presentation was 30 years with a male:female ratio of 1.03:1. They are commonly seen in the thoracic region (42.3%). The length of cyst was more than two vertebral levels in 85.81%. Mean symptom duration was 29 months, with most common presentation being that of compressive myelopathy. A good clinical outcome was present in symptomatic patients who had a shorter symptom duration and underwent complete surgical excision of the SEAC. Age, sex, length of lesion, and presence of dural defect did not have a bearing on the surgical outcome.

Conclusion For thoracic compressive myelopathy in a young patient, SEAC should be kept as a differential diagnosis. Surgical complete excision of the cyst with meticulous closure of the dural defect is the standard in management for a good clinical outcome.

Early microsurgery on thoracolumbar spinal extradural arachnoid cysts: Analysis of a series of 41 patients

BACKGROUND

We designed this study to share our management experiences on spinal extradural arachnoid cysts (SEACs) to add more to the body of evidence for their treatment.

METHODS

We retrospectively reviewed 41 patients who underwent microsurgery for thoracolumbar SEACs at our hospital from June 2009 to June 2019. All clinical data, including medical history, clinical features, imaging manifestation, operative findings, and prognosis, were extracted from medical records and databases. Perioperative differences of the Visual Analogue Scale (VAS), the Oswestry disability index (ODI) score, and postoperative Odom's criteria were used to assess the surgical outcome.

RESULTS

The most common and very first clinical symptom in the 41 patients was pain (VAS = 2.82 ± 0.89), and the mean ODI value was 61.7 ± 8.9%. Imaging revealed that the cystic lesions in the thoracolumbar spine involved an average of 2.85 segments. Of the 41 patients, 39 underwent total cyst excisions, and 36 had their dural defect repaired by one of three methods. The mean postoperative follow-up time was 52.3 months. Postoperatively, one case developed kyphoscoliosis and two cases experienced a recurrence. The majority of patients showed excellent outcomes according to Odom's criteria, the postoperative VAS (0.80 ± 1.08), and the ODI (15.4 ± 9.3%).

CONCLUSIONS

Themost commonclinicalsymptoms of thoracolumbar SEACs included progressive discomfort and pain around the involved spinal segments. Early surgical intervention relieved the patients from their symptoms. Microsurgery was recommended to resect the complete cyst and to repair the dural defect, but resection of the complete cyst is more necessary than just repairment of the dural defect for providing promising outcomes.

A Single Vertebral Surgical Approach for Spinal Extradural Meningeal Cysts Spanning Multiple Vertebral Segments by Auxiliary Neuroendoscope

BACKGROUND

Spinal extradural meningeal cysts (SEMCs) are rare lesions, especially those spanning multiple vertebral segments, and the surgical strategy has remained controversial. In the present study, we have described the outcomes of 4 patients with SEMCs treated with dural defect repair alone assisted by neuroendoscopy.

METHODS

From January 2018 to January 2020, 4 patients with SEMCs spanning multiple vertebral segments had undergone single-vertebral laminectomy or hemilaminectomy.

RESULTS

The SEMCs in all 4 patients had spanned multiple vertebral segments, from T11 to L2. Using magnetic resonance imaging, the location of the dural defect was predicted correctly for 3 patients. Single-vertebral laminectomy was used in 2 patients and single-vertebral hemilaminectomy in 2 patients. Intraoperatively, the entire cyst, including the upper pole, lower pole, and middle segment of the cyst, was explored using neuroendoscopy. In each patient, only 1 dural defect was found, which had been located in the middle segment of the cyst (T12-L1). All cyst dural defects had been sutured under a microscope. In all cases, the cyst wall was not removed. Postoperatively, the symptoms for all the patients had improved significantly, and subsequent magnetic resonance imaging studies showed obvious cyst regression. During the follow-up period of 15-44 months, no recurrence was observed.

CONCLUSIONS

For SEMCs spanning multiple vertebral segments, dural defect repair without cyst wall resection through single-vertebral hemilaminectomy or laminectomy can be effective. Intraoperative neuroendoscopy can assist, not only in finding the dural defect, but also in avoiding the omission of multiple dural defects as much as possible.

Microsurgical treatment of symptomatic spinal extradural arachnoid cyst: a consecutive case series of 34 patients and literature review

PURPOSE

A spinal extradural arachnoid cyst (SEAC) is a rare condition with unclear etiology. Herein, we report a series of symptomatic SEACs to illustrate features of SEACs in adults, surgical management, and outcomes.

METHODS

A total of 34 consecutive patients who underwent microsurgical treatment were retrospectively reviewed. Patient characteristics were recorded in each case, including presenting symptoms, imaging findings, neurologic status, a surgical procedure performed and follow-up.

RESULTS

There were 19 (56%) male and 15 (44%) female patients, with the ages ranging from 16 to 71 years (average 45 years). The lesions were located in the cervical segment (n = 4, 12%), thoracic segment (n = 6, 18%), thoracolumbar segment (n = 10, 29%) and lumbar segment (n = 14, 41%). Clinical presentations included back pain (n = 18, 53%), sensory deficits (n = 14, 41%), weakness (n = 4, 12%) and gait ataxia (n = 4, 12%), with a mean duration of symptoms of 17 months. The lesion was hypointense with the spinal cord on T1-weighted images and hyperintense on T2-weighted images and showed no homogeneous enhancement after contrast medium injection. Communication between the cyst and subarachnoid space was found in 23 patients and the cyst was resected after fistula ligation. Postoperatively, patients were followed up for an average of 80 months. The patients' symptoms dramatically improved and follow-up radiological images showed a complete disappearance of the cyst in all patients. No recurrence was observed in the dural repair group.

CONCLUSION

Patients with symptomatic SEAC present with obvious and persistent symptoms. Complete microsurgical cyst removal with the closure of the dural defect is the standard treatment procedure with good results and a low recurrence rate.

Transforaminal endoscopic excision of bi-segmental non-communicating spinal extradural arachnoid cysts: A case report and literature review

BACKGROUND

Spinal extradural arachnoid cysts (SEACs) are a rare cause of spinal cord compression. Typically, these cysts communicate with the intradural subarachnoid space through a small defect in the dural sac. For symptomatic SEACs, the standard treatment is to remove the cyst in total with a (hemi)laminectomy or laminoplasty. We present a rare case of bi-segmental non-communicating SEACs and describe our experience of using an endoscopic minimal access technique to remove bi-segmental non-communicating SEACs.

CASE SUMMARY

A 79-year-old female presented with pain related to bi-segmental SEACs at the T11-L1 segments. She underwent sequential transforaminal percutaneous endoscopic thoracic cystectomy of the SEACs. Following her first procedure, spinal magnetic resonance imaging demonstrated complete excision of the cyst at the T12-L1 segment. However, the cyst at the T11-T12 segment was still present. Thus, a second procedure was performed to remove this lesion. The patient’s right-sided lumbar and abdominal pain improved significantly postoperatively. Her Japanese Orthopaedic Association score increased from 11 to 25, her visual analogue scale score was reduced from 8 to 1. The physical and mental component summary of the 36-item short-form health survey (SF-36) were 15.5 and 34.375 preoperatively, and had increased to 79.75 and 77.275 at the last follow-up visit, respectively.

CONCLUSION

Bi-segmental non-communicating SEACs are extremely rare. Endoscopic surgery is a safe, effective, and reliable method for treating these cysts. In the event of bi-segmental SEACs, it is important to identify whether both cysts are communicating before surgery, and if not, to remove both cysts separately during the index surgery to avoid re-operation.

Surgical Treatment of Ten Adults with Spinal Extradural Meningeal Cysts in the Thoracolumbar Spine

Objective

To retrospectively analyze the clinical characteristics and surgical experience of 10 adults with spinal extradural meningeal cysts (SEMCs) in the thoracolumbar spine which may further provide evidence for surgical decision-making.

Methods

Ten adults with SEMCs in the thoracolumbar spine were surgically treated and enrolled in this study. Clinical manifestations, imaging data, intraoperative findings and postoperative outcome were recorded.

Results

Clinical manifestations of SEMCs included motor and sensory dysfunction of the lower limbs and urination and defecation disturbance. The cysts presented as intraspinal occupying lesions dorsal to the spine, ranging from the T8 to L3 level. Defects of eight cases were found on preoperative magnetic resonance imaging (MRI). Selective hemilaminectomy or laminectomy were used to reveal the defect within the cyst, which was further sutured with microscopic technique. The final outcome was excellent or good in seven cases and fair in three cases. No recurrence was observed during follow-up.

Conclusion

SEMCs are rare intraspinal cystic lesions. Radiography and MRI are clinically practical methods to assess defects within SEMCs. Selective hemilaminectomy or laminectomy may reduce surgical trauma. Detection and microscopic suturing of the defects are the key steps to adequately decompress the nervous tissue and prevent postoperative recurrence.

Extradural arachnoid cyst with bony erosion: a rare case report

The authors present the case of an otherwise healthy 38-year-old female with an atypical extradural arachnoid cyst with multi-level involvement in the lumbar spine leading to left quadriceps weakness and dysesthesia. Upon presentation, a lumbar spine MRI with contrast and plain radiographs revealed extensive L4 bony erosion. An MR angiogram and cervical spine MRI with contrast were then obtained in order to rule out any aortic root or cervical spine pathology. With no other apparent clinically relevant pathology revealed by these additional tests, an L3-5 posterior decompression and fusion procedure was performed. Her preoperative symptoms were successfully resolved following the procedure, with no resultant surgical complications. The cyst is atypical not only due to its size and location, but also due of the significant bony erosion of the left L4 pedicle and vertebral body. To the authors' knowledge, this is the first reported case of an extradural arachnoid cyst in the lumbar spine with bony erosion of the pedicle and vertebral body. In cases such as this, a CT myelogram may be useful in planning the operative approach through visualization of the exact communication between cyst and dura. This approach may also aid in diagnosing and identifying atypical cyst presentations such as the one presented here.

Extradural thoracic meningeal cyst without spinal dysraphism causing adulthood myelopathy: Case illustration and review of the literature

Extradural spinal meningeal cysts are rare lesions in the adult spine and are an uncommon cause of neurologic deficits. We present the case of an adult who presented with myelopathic symptoms related to a dorsally based extradural thoracic meningeal cyst in the absence of any defect in the posterior spinal elements and no history of spinal dysraphism or trauma. We also performed a review of the literature to evaluate the surgical techniques for extradural meningeal cysts. Most thoracic cysts are intradural arachnoid cysts, yet this lesion is an extradural meningeal cyst, not an intradural arachnoid cyst. Because of the rarity of this lesion, its anatomic characterization can be difficult to conceptualize. An artist's illustration helps illustrate the anatomic characteristics of this cyst and our surgical management.

True Dural Spinal Epidural Cysts: Report of 5 Cases

BACKGROUND

Spinal arachnoid cysts are a rare cause of compressive myelopathy. Spinal extradural arachnoid cysts (SEACs) are even rarer.

METHODS

We retrospectively reviewed the SEACs operated on in our hospital between 2015 and 2019, according to their clinical and radiologic findings, treatments performed, and outcomes.

RESULTS

We identified 5 cases (2 males and 3 females), ranging in age from 21 months to 78 years. Except for the pediatric case, all patients presented with pain and 3 had some grade of neurologic impairment. Preoperative magnetic resonance imaging showed multiloculated cyst in 4 cases, and the communication with the dura was properly identified in only 1 case. The patients were operated through a laminectomy or laminoplasty and total removal of the cyst, and the communication with the dura was identified and repaired in all cases. In all cases, the defect was near the exit of a nerve root, and rootlets were seen through it, producing a ball-like valve mechanism. Histology of the cyst wall showed true dura in every case. One patient needed a reoperation for evacuation of a fluid collection (related to the dural sealant). Following Odom's criteria, 3 patients had an excellent outcome and 2 had a fair outcome.

CONCLUSIONS

Total excision of a symptomatic SEAC through either laminectomy or laminoplasty is a safe and effective treatment option. Although isolated repair of the dural communication without cyst removal may seem appealing, we have found it very difficult to identify the point of communication preoperatively.