Synovial cysts of the lumbar spine: surgery-related results and outcome

Cysts of the ligamentum flavum are often linked to ischemic conditions: A morphological study

"Cysts of the ligamentum flavum (cysts-LF)" is the term for non-neoplastic cystic lesion involving LF. The aim of the present study was to elucidate the histopathological characteristics and pathogenesis of "cysts-LF". Herein, we defined cysts-LF as spinal cysts containing degenerative LF components. From archival cases, we investigated 18 symptomatic cysts-LF surgically removed from 18 patients (13 males and five females; median age 68.5 years [range, 42-86 years]). The elastic fibers of LF components in the wall were separated and/or torn, and cyst walls were accompanied by chondroid metaplasia (17 cases), myxoid changes (13 cases), ossification (11 cases), amyloid deposits (14 cases), hemosiderosis (six cases), granular/smudgy calcification (four cases), synovial cell linings (three cases), and severe inflammatory infiltrates (one case). These histologic features of our cysts-LF were shared by previously reported "cysts-LF." Fourteen cysts-LF demonstrated vascular stenosis/occlusion, and eight showed thick hyalinized vessels, suggesting local circulatory insufficiency. Eight cases (44%) exhibited lipomembranous fat necrosis, accompanied by hyalinized vascular changes (p = 0.003). Ischemic conditions were observed in nearly half of the present cysts-LF, and may be one of the main contributing factors for the formation of cysts-LF, via degeneration and cystic changes in the LF.

Decompression with or without Fusion for Lumbar Synovial Cysts—A Systematic Review and Meta-Analysis

The management of symptomatic lumbar synovial cysts (LSC) is still a matter of debate. Previous systematic reviews did not stratify data according to different treatment techniques or incompletely reported comparative data on patients treated with lumbar posterior decompression (LPD) and lumbar decompression and fusion (LDF). The aim of our study was to compare LPD and LDF via a systematic review and meta-analysis of the existing literature. The design of this study was in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The review questions were as follows: among patients suffering from symptomatic lumbar synovial cysts (population) and treated with either posterior lumbar decompression or posterior decompression with fusion (intervention), who gets the best results (outcome), in terms of cyst recurrence, reoperation rates, and improvement of postoperative symptoms (comparison)? The search of the literature yielded a total of 1218 results. Duplicate records were then removed (n = 589). A total of 598 articles were screened, and 587 records were excluded via title and abstract screening; 11 studies were found to be relevant to our research question and were assessed for eligibility. Upon full-text review, 5 were excluded because they failed to report any parameter separately for both LPD and LDF. Finally, 6 studies for a total of 657 patients meeting the criteria stated above were included in the present investigation. Our analysis showed that LDF is associated with better results in terms of lower postoperative back pain and cyst recurrence compared with LPD. No differences were found in reoperation rates and complication rates between the two techniques. The impact of minimally invasive decompression techniques on the different outcomes in LSC should be assessed in the future and compared with instrumentation techniques.

Minimally Invasive Posterior Tubular Microsurgical Approach for the Management of Symptomatic Synovial Cysts of the Lumbar and Cervical Spine

BACKGROUND

Synovial cysts are commonly associated with instability. Whether to fuse patients is a matter of controversy. Simple resection may offer favorable clinical outcomes but may come at the expense of recurrence rate. We describe our experience with the minimally invasive management of these lesions using microsurgical dissection through a tubular retractor system.

MATERIALS

A retrospective cohort study of symptomatic patients with synovial cysts treated by a minimally invasive tubular approach from 2001 to 2018 was performed. We evaluated variables such as preexisting spinal pathology, previous surgery, radiological findings, comorbidities, and secondary surgery requiring fusion. We used the visual analog scale (VAS), the Oswestry disability index (ODI), and the Macnab scale for clinical evaluation.

RESULTS

There were 35 patients with a mean age of 63 years. The mean duration of symptoms before surgery was 195 weeks. Axial pain was present in 77.1% of cases; radiculopathy was the main symptom in 94.3% of cases. The most frequent site was L4-L5 (62.8%). Presenting comorbidities were lumbar stenosis (28.6% of patients), spondylolisthesis (8.6%), and facet hypertrophy (31.4%). Mean surgical time was 143 minutes (range, 55-360 minutes). The mean hospital stay was 2 days, ranging from 1 to 5 days. No complications were encountered as a consequence of the surgical procedure. All patients showed neurophysiological improvement after surgical intervention. A total of 34 patients (97.14%) showed clinical improvement at the end of follow-up, averaging 17 months and ranging from 1 to 60 months, 28 patients (80%) had good to excellent Macnab outcomes, 6 patients (17.14%) were rated as fair, and 1 (2.86%) patient had a poor Macnab outcome. Radicular VAS significantly changed (P < .05) from a preoperative mean of 8.23 ± 1.24 to a postoperative mean of 2.23 ± 1.94. ODI significantly decreased (P < .05) from a preoperative of mean of 41.02 ± 12.56 to a postoperative of mean of 11.82 ± 10.56. We performed fusion at initial surgery in 37.1% of cases; however, 3 more patients required secondary fusion at follow-up.

CONCLUSION

Our series corroborates the prior literature with a low incidence of synovial cysts in the cervical spine and none in the thoracic spine. The present work shows the efficacy of minimally invasive surgery in the treatment of these lesions. Synovial cysts were associated with instability, ultimately requiring fusion in the majority of patients. The authors' study includes a large patient series with minimally invasive microsurgical decompression performed through a tubular retractor to date.

LEVEL OF EVIDENCE

3.

LUMBAR SPINE SYNOVIAL CYST: A CASE SERIES REPORT AND REVIEW OF SURGICAL STRATEGIES

Lumbar spine synovial cysts are benign growths adjoining the facet joints that may induce low back pain, lumbar radiculopathy and neurological deficit. However, they are not well defined concerning their origin, cause and pathology, as well as available treatment strategies. The scope of different surgical procedures includes image-guided epidural steroid injection, direct cyst puncture by percutaneous epidural needle, spinal canal decompression and cyst resection, and spinal bone fusion with/without instrumentation. Hereby, we report institutional experience and discuss surgical strategies of lumbar spine synovial cyst treatment. Presenting symptoms, imaging findings and outcomes were retrospectively analyzed in 15 patients with lumbar spine synovial cyst, operated on during a one-year period. The leading presenting symptom was lumbar radicular pain, while the most commonly involved vertebral level was L5-S1. In a great majority of patients, a single-level interlaminectomy and cyst resection were performed. Most patients recovered without postoperative neurological and functional deficit, as well as surgery-related complications. No poor outcome was noticed in our series. Concerning our results and literature review, the optimal management for patients with symptomatic lumbar synovial cyst has to be highly personalized, which is essential to achieve a favorable outcome. Nonetheless, the best treatment strategy has yet to be affirmed.

[Lumbar synovial cysts: literature review and original long-term results after microsurgical resection]

BACKGROUND

Intraspinal lumbar vertebral joint cysts are an unusual cause of nerve root compression symptoms and do not differ clinically from the symptoms of a herniated disc.

PATHOGENESIS

The cysts originate from the small vertebral joints and, depending on their size, compress the nerval structures. The affected vertebral joints typically show activated arthritic circumstances, which are associated with degenerative spondylolisthesis in about 50% of cases. In the majority of cases, MRT and CT can be used for diagnostic purposes. The exact etiology has not been fully clarified; various factors such as activated arthritis of the vertebral joints appear to be the major cause.

TREATMENT

Treatment options include conservative, semi-invasive and surgical therapy. Conservative and semi-invasive treatment methods lead to temporary improvement. The result of surgical treatment, however, is excellent in a complete resection of synovial cysts. In In rare cases, an initial fusion is necessary in rare cases.

Surgical Treatment of Spinal Synovial Cysts in Elderly Patients: Symptoms, Treatment Course, and Outcome in Patients >75 Years of Age

BACKGROUND

With the aging of our society comes a rising number of elderly patients with progressive degeneration of the spine associated with synovial cysts. Surgical treatment may be particularly challenging in elderly patients because of comorbidities.

METHODS

Patients treated in our department between 1999 and 2014 for spinal synovial cysts were screened. The 28 patients ≥75 years old were classified as elderly and were compared with 96 patients 50-74 years old. No patient underwent fusion as part of cyst resection.

RESULTS

Despite a significantly higher frequency of muscle reflex changes in elderly patients at presentation, symptoms, cyst levels, rate of complications, and surgical method were not different between groups. Cyst adherence to the dura and subtotal resection were observed significantly more often in the elderly group (18% vs. 3%; P < 0.05). Outcome according to the Oswestry Disability Index was classified as no disability or minimal disability in 85% of the elderly group and in 82% of the control group. Recurrent cyst and delayed fusion rates were lower in the elderly group (4% and 4%) compared with the control group (7% and 8%).

CONCLUSIONS

The clinical course of elderly patients with surgical treatment of spinal synovial cysts did not differ compared with younger patients. Good or excellent results could be achieved and persisted for a long time in most cases. Fusion should be performed only in cases of severe instability. Nonaggressive cyst removal in cases of dural attachment enables low cerebrospinal fluid fistula rates without increasing cyst recurrence rates.

Lumbar ganglion cyst: Nosology, surgical management and proposal of a new classification based on 34 personal cases and literature review

AIM

To analyze different terms used in literature to identify lumbar extradural cysts and propose a common scientific terminology; to elaborate a new morphological classification of this pathology, useful for clinical and surgical purposes; and to describe the best surgical approach to remove these cysts, in order to avoid iatrogenic instability or treat the pre-existing one.

METHODS

We retrospectively reviewed 34 patients with symptomatic lumbar ganglion cysts treated with spinal canal decompression with or without spinal fixation. Microsurgical approach was the main procedure and spinal instrumentation was required only in case of evident pre-operative segmental instability.

RESULTS

The complete cystectomy with histological examination was performed in all cases. All patients presented an improvement of clinical conditions, evaluated by Visual Analogic Scale and Japanese Orthopaedic Association scoring.

CONCLUSION

Spinal ganglion cysts are generally found in the lumbar spine. The treatment of choice is the microsurgical cystectomy, which generally does not require stabilization. The need for fusion must be carefully evaluated: Pre-operative spondylolisthesis or a wide joint resection, during the operation, are the main indications for spinal instrumentation. We propose the terms "ganglion cyst" to finally identify this spinal pathology and for the first time its morphological classification, clinically useful for all specialists.

Minimally invasive surgery for lumbar synovial cysts with coexisting degenerative spondylolisthesis

BACKGROUND

About one third of lumbar synovial cysts are associated with degenerative spondylolisthesis. Segmental instability is thought to contribute to the pathogenesis and recurrence of synovial cysts and lumbar fusion has been advocated as a treatment of choice in the presence of spondylolisthesis. In patients with spondylolisthesis, minimally invasive resection of lumbar synovial cysts, without fusion, could minimize surgically induced segmental instability while providing good pain relief.

METHODS

Clinical and radiological outcomes of lumbar synovial cyst patients with and without spondylolisthesis were retrospectively compared. Pain outcomes were assessed with modified Macnab criteria.

RESULTS

Fifty-three patients (18 with grade 1 spondylolisthesis) underwent minimally invasive synovial cyst resection and all had either excellent or good pain outcome at ≤ 8 post- operative weeks (P = 1.000, n = 53). At > 8 post-operative weeks (mean (SD) follow-up of 200 (175) weeks), excellent or good outcomes were noted in 89% of patients without spondylolisthesis and in 75% of patients with spondylolisthesis (P = 0.425, n = 40). Four patients developed a new grade 1 spondylolisthesis at a mean follow-up of 2.6 ± 2.1 years. Nine patients were assessed for spondylolisthesis measurements at 1.2 ± 1.3 years of follow up and no significant difference was observed (5 ± 0 vs 5 ± 1 mm; P = 0.791). Two patients without spondylolisthesis and none of the patients with spondylolisthesis had a synovial cyst recurrence.

CONCLUSION

Patients with concomitant lumbar degenerative spondylolisthesis and synovial cyst can have good short- and long-term clinical outcomes with minimally invasive surgery without fusion. Post-operative segmental instability does not appear to be significant in patients with spondylolisthesis. All patients included in this article signed an informed consent for the use of their medical information for research.

Juxtafacet Spinal Synovial Cysts

STUDY DESIGN

This was a retrospective study.

PURPOSE

To study the surgical outcome of synovial cysts of the lumbar spine through posterior laminectomy in combination with transpedicular screw fixation.

OVERVIEW OF LITERATURE

Synovial cysts of the lumbar spine contribute significantly to narrowing of the spinal canal and lateral thecal sac and nerve root compression. Cysts form as a result of arthrotic disruption of the facet joint, leading to degenerative spondylolisthesis in up to 40% of patients.

METHODS

Retrospective data from 6 patients, treated during the period of March 2007 to February 2011, were analyzed. All preoperative and postoperative manifestations, extension/flexion radiographs, magnetic resonance imaging, and computed tomography records were reviewed. All underwent surgery for synovial cysts with excision and decompression combined with posterior fixation. The result of surgery was evaluated with Macnab's classification. An excellent or good outcome was considered as satisfactory. Japanese Orthopedic Association Scale was used for evaluation of back pain.

RESULTS

All patients included in this study had excellent outcomes as regarding to improvement of all preoperative manifestations and returning to normal daily activities. Only 2 cases developed postoperative transient cerebro-spinal fluid leak and were treated conservatively and improved during the follow up period.

CONCLUSIONS

Although this study included a small number of cases and we could not have statistically significant results, the good outcome of decompression of synovial cysts combined with posterior fixation and fusion encouraged us to recommend this approach for patients with juxtafacet synovial cysts.

Surgical excision of a Juxtafacet cyst in the lumbar spine: A report of thirteen cases with long-term follow up

CONTEXT

Juxtafacet cysts of the lumbar spine are extradural degenerative lesions associated with symptoms of lower back pain and radiculopathy. Surgical treatment is indicated when there is failure of conservative measures. Primary spinal fusion at the time of surgical excision of the cyst is a matter of controversy. Few reports have described long-term follow-up for surgical treatment of spinal cysts.

AIM

The purpose of this study is to assess the long-term outcome of the surgical excision of a Juxtafacet cyst without spinal fusion.

STUDY DESIGN

This is a retrospective case series study, level IV evidence.

MATERIALS AND METHODS

This is a retrospective case series study on 13 patients with Juxtafacet cysts, who were treated with surgical excision of the cysts without spinal fusion. A questionnaire scoring system was used for evaluation of the surgical outcome.

RESULTS

The study was conducted on 13 patients, seven females (54%) and six males (46%), their age ranging from 38 to 69 years, with a mean age of 52 (±9.93 STD) years. The mean duration of the symptoms was 10.5 (±6.22 STD) months. All patients got benefit from surgery, with six excellent (46%), six good (46%), and one fair outcome (8%), with no surgery-related complications. The mean follow-up period of the patients at the time of this study was 4.2 years (±1.43 STD).

CONCLUSION

Long-term follow-up for surgical excision of symptomatic Juxtafacet cysts without spinal fusion revealed excellent to good results in 92% of the patients, with a satisfaction rate of 80% (±8.41 STD).

Chiropractic management of a patient with lumbar spine pain due to synovial cyst: a case report

INTRODUCTION

The purpose of this study is to report the findings resulting from chiropractic care using flexion distraction spinal manipulation for a patient with low back and radicular pain due to spinal stenosis caused by a synovial cyst.

CASE REPORT

A 75-year-old man presented with low back pain radiating to the right anterior thigh and down the left posterior leg of 3 years' duration. Physical and imaging examinations showed a synovial cyst-induced spinal stenosis at the right L3-L4 level and bilateral L4-L5 spinal stenosis.

INTERVENTION AND OUTCOMES

Flexion distraction spinal manipulation and physiological therapeutics were applied at the levels of stenosis. After 4 visits, the patient noted total absence of the right and left lower extremity pain and no adverse reaction to treatment. After 3 months of treatment and 16 visits, his low back and buttock pain were minimal; and he had no leg pain.

CONCLUSION

Lumbar synovial cyst and stenosis-generated low back and radicular pain was 80% relieved in a 75-year-old man following Cox flexion distraction spinal manipulation.

The diagnosis and management of synovial cysts: Efficacy of surgery versus cyst aspiration

Background:

The surgical management of lumbar synovial cysts that have extruded into the spinal canal remains controversial (e.g. decompression with/without fusion).

Methods:

The neurological presentation, anatomy, pathophysiology, and surgical challenges posed by synovial cysts in the lumbar spine are well known. Neurological complaints typically include unilateral or, more rarely, bilateral radicular complaints, and/or cauda equina syndromes. Anatomically, synovial cysts constitute cystic dilatations of synovial sheaths that directly extrude from facet joints into the spinal canal. Pathophysiologically, these cysts reflect disruption of the facet joints often with accompanying instability, and potentially compromise both the cephalad and caudad nerve roots.

Results:

Aspiration of lumbar synovial cysts, which are typically gelatinous and non-aspirable, and typically performed by “pain specialists” (e.g. pain management, rehabilitation, radiologists, others) utilizing fluoroscopy or CT-guided aspiration, is associated with 50–100% failure rates. Surgical decompression with/without fusion (as the issue regarding fusion remains unsettled) results in the resolution of back and radicular pain in 91.6–92.5% and 91.1–91.9% of cases, respectively.

Conclusions:

After a thorough review of the literature, it appears that the treatment with the best outcome for patients with synovial cysts is cyst removal utilizing surgical decompression; the need for attendant fusion remains unsettled. The use of an alternative treatment, percutaneous aspiration of cysts, appears to have a much higher recurrence and failure rate, but may be followed by surgery if warranted.

Synovial cyst of the thoracic spine: case report

Spinal cord compressing syndrome due to synovial cyst (SC) of the thoracic spine is a rare clinic condition. We report a case of SC located in the thoracic spine causing spastic paraparesis in a 14 year-old female patient. The SC was removed thoroughly by laminectomy. The patient had an excellent recovery. The etiological and therapeutic aspects are discussed.

Microdecompression for lumbar synovial cysts: an independent assessment of long term outcomes

Background

Outcomes of surgical intervention for lumbar synovial cysts have been evaluated in the short and intermediate term. Concerns regarding cyst recurrence, the development of late instability at the involved level, and instability/stenosis at adjacent levels (when concomitant) fusion is performed suggest that long term follow-up is needed. This study aims to fill that void.

Methods

Forty-six patients operated by a single surgeon not involved in the study were followed up long term at an average of 9.7 years (range 5 to 22 years) post-operatively. All patients underwent decompression (+/- concomitant arthrodesis in the presence of associated degenerative spondylolisthesis) using the operative microscope for magnification/illumination. Outcomes were assessed using a customized questionnaire evaluating: relief of pain/claudicant symptoms, numbness/parasthesias, and weakness; as well as late onset low back pain, new radicular symptoms, need for additional surgery, and patient satisfaction. Outcomes in patients with or without fusion were compared as well.

Results

87% of patients noted resolution of their pre-operative pain, numbness, and weakness. 28% of patients developed late onset low back pain. 17% developed late onset radicular symptoms in a new nerve root distribution. 15% required subsequent additional surgery. 89% of patients were satisfied with the surgical outcome. No differences were found for any outcome measure between patients undergoing concomitant fusion and those undergoing decompression alone using the two-sample t-test.

Conclusion

This study provides outcome data at an average of nearly ten years post-operative. This information should allow surgeons to provide realistic expectations for their patients regarding outcomes and should enhance the informed consent and surgical decision-making process.

Spinal lumbar synovial cysts. Diagnosis and management challenge

Sophisticated and newer imaging capabilities have resulted in increased reporting and treatment options of spinal lumbar synovial cysts (LSS). Most of the patients with lumbar cysts tend to be in their sixth decade of life with a slight female predominance. The incidence of LSS is thought to be less than 0.5% of the general symptomatic population. They may be asymptomatic and found incidentally or the epidural growth of cysts into the spinal canal can cause compression of neural structures and hence associated clinical symptoms. Most of the symptomatic LSS patients present with radicular pain and neurological deficits. Spinal synovial cysts are commonly found at L4-5 level, the site of maximum mobility. They may be unilateral or bilateral and at one or multilevel. MRI is considered the tool of choice for its diagnosis. The etiology of LSS is still unclear, but underlying spinal instability, facet joint arthropathy and degenerative spondylolisthesis has a strong association for worsening symptoms and formation of spinal cysts. Synovial cysts resistant to conservative therapy should be treated surgically. Resection and decompression with or without fusion and instrumentation remains an appropriate option. Synovial cysts may recur following surgery. The optimal approach for patients with juxtafacet LSS remains unclear. The best surgical treatment option for each particular individual should be tailored depending upon the symptoms, radiological findings and other co morbidities.

Retrospective study of 77 patients harbouring lumbar synovial cysts: functional and neurological outcome

BACKGROUND

Synovial cysts represent an uncommon and probably underestimated pathological entity of the degenerative lumbar spine. The authors report a retrospective analysis of the clinical presentation, radiological studies and operative findings in 77 patients surgically treated for symptomatic lumbar synovial cysts at their institution.

MATERIALS AND METHOD

Between January 1992 and June 1998, a total of 77 patients presenting with symptomatic lumbar synovial cysts were operated on in the author's department. Operative procedure, complications, results and pathological findings were correlated with preoperative assessment. There were 41 men and 36 women with an average age of 63 years (range 44-90 years).

RESULTS

On the basis of their symptom complex on presentation, two populations were identified: patients who presented with a single radicular pain (group I = 51 patients), and patients who presented with bilateral neurogenic claudication (group II = 26 patients). Neurological examination on presentation demonstrated motor deficit (12%), sensory loss (26%) and reflex changes (35%). Degenerative disc disease and facet joint osteoarthritis was a frequent finding in patients with pre-operative MRI. Facet joint orientation was >45 degrees in 76.6% of patients. Preoperative spondylolisthesis was found in 48% on radiological studies. All the patients were treated surgically with resection of the cyst. No fusion was performed as a first line procedure. However subsequent fusion was necessary in one patient who developed symptomatic spondylolisthesis. Mean follow-up period was of 45 months ranging from 18 to 105 months. Only one recurrence occurred during the follow-up period. An excellent or good functional outcome was seen in 97.4% of cases, and 89% of the patients with motor deficit recovered.

CONCLUSIONS

Surgical resection of lumbar synovial cysts is an effective treatment associated with very low morbidity. Synovial cysts are associated with increased grade and frequency of facet joint asteoarthritis but not with increased grade or frequency of degenerative disc disease compared with patients without cysts. In the author's opinion, at the present time, there is no reliable criterion which allows the development of a symptomatic spinal instability to be predicted in patients with a preoperative spondylolisthesis and therefore fusion as a first line procedure is still debatable.

Lumbar synovial cysts of the spine: an evaluation of surgical outcome

OBJECTIVE

Our aim was to study the outcomes and results of surgically treated patients with synovial cysts of the lumbar spine in our institution.

METHODS

Retrospective data from 39 consecutive patients, treated during the period of December 1996 to August 2004, were analyzed. Twenty-eight men (70%) and 11 women (30%) of mean age 63.3 years were studied. All pre- and postoperative signs, symptoms, extension/flexion radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) with or without myelography were reviewed. All underwent surgery for synovial cysts with excision and decompression. Additional fusion in 26 patients was performed; 22 of them had degenerative spinal spondylolisthesis. Nine (23%) patients had prior decompression procedures, with three (8%) having had prior spinal instrumentation. Surgical outcomes were evaluated according to a questionnaire scoring system (scale of 1-4; 4 = excellent, 3 = good, 2 = fair, 1 = poor). Various preoperative attributes such as gender, age, weight, and height were analyzed to see if they had any effect on the outcome of surgery. Modified musculoskeletal outcomes data evaluation and management system (MODEM), questionnaire was provided to all; 24 (62%) responded. The following categories were determined: excellent (<20), very good (21-40), good (41-60), fair (61-80), and poor (81-100). Postoperative complications were also recorded.

RESULTS

All patients had pain in their lower extremities, with 62% experiencing pain bilaterally. Ninety-five percent had pain in their back and 36% in the buttocks (36%). Eighteen (46%) patients had CT myelography. A total of 42 cysts were found. Two patients had bilateral cysts at L4-L5 level. Histology revealed two hemorrhagic cysts. The average duration of surgery was 231 minutes (range 92-391 minutes), and a mean blood loss of 930 mL (range 200-2500 mL) was recorded. Two operative dural tears and one postoperative wound dehiscence were observed. One patient had a recurrent synovial cyst at the site of original surgery. Eight patients (four each in the fusion and nonfusion group) had junctional degeneration and symptoms. A regression analysis performed on age, height, weight, and gender showed that they were not determining factors of surgical outcome. Surgery of spinal cysts at L4-L5 segment produced good and those at L5-S1 and multilevel excellent results. Patients with spinal segment fusion had superior outcomes, with 80% having excellent or good outcomes versus approximately 70% without fusion. With the modified MODEM questionnaire, 22 of the 24 (92%) patients scored between excellent, very good, and good. Two patients scored in the fair range, and none of the 24 patients scored in the range of poor.

CONCLUSIONS

Spinal cysts are commonly found at the L4-L5 level, the site of maximum instability. MRI is the tool of choice for diagnosis. The etiology is still unclear, but underlying spinal instability has a strong association for formation of spinal cysts and worsening symptoms. Synovial cysts resistant to conservative therapy should be treated surgically. Resection and decompression with fusion remain an appropriate option. The optimal approach for patients with juxtafacet cysts remains unclear. The best surgical treatment approach for each particular individual appears to remain speculative.

Synovial cysts of the thoracic spine

OBJECT

Thoracic synovial cysts (TSCs) are rare and are usually the subject of case reports. The authors studied the clinical manifestations, radiological aspects, and surgical treatment in a series of patients at their institution who harbored TSCs. They also review the literature to discuss the potential factors involved in the pathogenesis of this lesion.

METHODS

A database search of 16,000 patients who underwent decompressive spine surgery at the Mayo Clinic (Rochester, MN) between 1976 and 2003 disclosed nine patients (0.06%) in whom a diagnosis of TSC had been made. All patients were men. The mean age at presentation was 73 +/- 5 years and mean duration of symptoms was 5 +/- 3 months. The mean duration of follow up was 4 +/- 3 years. The patients had no history of trauma or spine surgery. All patients had spastic paraparesis; two had urinary difficulties. Detailed neurological examination revealed myelopathy and radiculopathy with a sensory level of T10-L4. Magnetic resonance imaging revealed bilateral cysts in four patients and unilateral lesions in five. Three of the cysts were at the T-10 interspace, seven at the T-11 interspace, and three at the T-12 interspace. Seven cysts were on the right and six were on the left. Computerized tomography myelography performed in five patients revealed a gas bubble in the TSC in two patients. All patients underwent laminectomy/partial facetectomy, excision of the cyst, and decompression of the thecal sac and nerve root without any complications. None of these patients underwent a fusion. Eight patients (89%) experienced moderate to excellent relief of their preoperative signs and symptoms and one patient (11%) remained stable. There was no evidence of cyst recurrence at the site of surgery or other spinal segments at follow-up examination in any patient.

CONCLUSIONS

When compared with their lumbar and cervical spine counterparts, TSCs are exceedingly rare. Their rarity may be explained by the decreased mobility of the thoracic spinal segments. The origin of TSCs is more likely degenerative rather than traumatic. Based on their experience and the follow-up duration, surgery provided durable relief from symptoms.