Prevalence and clinical features of intraspinal facet cysts after decompression surgery for lumbar spinal stenosis

Efficacy of Percutaneous Image-Guided Rupture of Lumbar Facet Cysts: A Retrospective Study

Background

Percutaneous rupture of lumbar facet cysts (LFC) is the only nonsurgical treatment which is effective in directly reducing cysts. However, this is not yet a common procedure, and its effectiveness, including the associated complications, remains unclear. Therefore, this study aimed to evaluate the clinical outcomes of percutaneous rupture for LFC and elucidate whether this minimally invasive procedure could become an alternative to surgeries for cases resistant to conservative treatments.

Methods

This study investigated 57 symptomatic patients with LFC for whom conservative treatments were ineffective and underwent percutaneous rupture of the LFC. All patients were followed up for >2 years posttreatment. Clinical evaluations (visual analogue scale (VAS) and recovery rate calculated using the Japanese Orthopedic Association (JOA) scores) and radiographic evaluations (size of LFC based on magnetic resonance imaging (MRI)) were performed from pretreatment to the final follow-up examination.

Results

Successful LFC rupture, without hospitalization and general anesthesia, was achieved in 48 patients. No severe complications occurred during treatment through the last observation. Satisfactory clinical results with significant improvements in the VAS and JOA scores were obtained (VAS: pre/posttreatment: 80.7 mm/11.2 mm, JOA: pre/posttreatment: 15.6 points/26.7 points, and recovery rate: 82.3%). A significant reduction in the LFC was also observed in all cases based on the posttreatment MRI findings. No successful rupture cases required subsequent surgical treatments, although four cases of LFC recurrence required additional percutaneous rupture treatment.

Conclusions

Percutaneous rupture for LFC is not only a safe and minimally invasive procedure without any severe complications or requirements for hospitalization and general anesthesia but also a beneficial procedure that can eliminate the need for surgery in cases resistant to conservative treatments.

Synovial facet joint cysts after lumbar posterior decompression surgery

OBJECTIVE

Numerous studies have reported on synovial facet joint cysts of the spine as a primary lesion. The exact pathogenesis of those cysts is still controversial, but degeneration and destabilization seem to be underlying mechanisms. However, only a few reports have thus far investigated synovial cysts of the spine as postoperative complications of decompression surgery. In this retrospective clinical study, the authors focused on synovial cysts of the lumbar facet joints as complications after lumbar decompression surgery, with the aim of elucidating their pathophysiology.

METHODS

A total of 326 patients with 384 segments treated with posterior decompression surgery without fusion were included in the study. Of these segments, 107 were surgically decompressed unilaterally and 277 were decompressed bilaterally. After surgery, 18 of the 384 segments developed a complication of symptomatic facet synovial cyst. The anatomical and morphological evaluations of these segments were performed using functional plain radiographs, CT scans, and MR images.

RESULTS

All of the 18 segments with postoperative lumbar facet synovial cyst were treated with bilateral lumbar posterior decompression. There was no significant radiological lumbar spinal instability in any segments, although 17 of 18 segments demonstrated facet articular spondylotic changes. Moreover, 12 of 18 patients demonstrated lumbar retrolisthesis in the neutral position.

CONCLUSIONS

Based on the authors' results, they propose that patients with lumbar degenerative disease who have a potential biomechanical lumbar instability such as disruption of the facet articular surface and hydrarthrosis or lumbar facet tropism might have a high risk for formation of lumbar facet synovial cyst after bilateral posterior decompression surgery.

Clinical Outcomes of Minimally Invasive Posterior Decompression for Lumbar Spinal Stenosis with Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare the clinical outcomes 5 years after minimally invasive posterior decompression for lumber spinal stenosis (LSS) between patients with and without degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

Indications for surgical procedures for patients with LSS and DS are still under investigation. Since minimally invasive surgery does not affect most anatomical structures, preoperative DS may not negatively affect the clinical outcomes of minimally invasive posterior decompression.

METHODS

Overall, 198 patients with LSS who underwent microendoscopic or microscopic decompression and were followed up for more than 5 years postoperatively were included in the present study. Patients who showed a segmental kyphosis >5° at the surgical level during flexion were treated with fusion surgery. However, other patients, including those with DS, were treated with posterior decompression. The patients were divided into two groups: the DS group included 82 patients with >3-mm slip and the non-DS group included 112 patients with ≤3-mm slip or without slip. A mixed-effects model adjusted for age and sex was used to compare the improvements in the visual analog scale score for low-back pain and the Japanese Orthopaedic Association score of the two groups. For subgroup analysis (n = 53), the changes in the preoperative physical component summary and the mental component summary of Short Form-36 of the two groups at 5 years after surgery were evaluated.

RESULTS

There was no significant difference in the improvement of preoperative low-back pain visual analog scale score and Japanese Orthopaedic Association score 5 years after surgery between the two groups. Subgroup analysis showed no significant difference between the two groups in the improvement of preoperative physical component summary and mental component summary 5 years after surgery.

CONCLUSION

After carefully eliminating patients with segmental instability, DS did not affect the clinical outcomes of minimally invasive decompression surgery.Level of Evidence: 3.

Rapid Spontaneous Resolution of Lumbar Intraspinal Facet Cyst after Lateral Lumbar Interbody Fusion

Introduction

Intraspinal facet cysts resistant to conservative treatment are treated surgically. Surgical treatment was generally resection and decompression, but complications of dural tear and recurrence sometimes occurred. We present good clinical results and rapid spontaneous resolution following treatment of five cases of lumbar intraspinal facet cyst after lateral lumbar interbody fusion (LLIF).

Methods

Multicenter series of five cases of lumbar intraspinal facet cyst with segmental instability treated with LLIF. The cross-sectional area (CSA) of the thecal sac and facet cyst on T2-weighted axial magnetic resonance imaging and the distance of facet joint (FJ) gap on axial computed tomography were measured preoperatively and postoperatively. Patient data and clinical and radiographic results were described.

Results

Of five patients, one was male and four were female, with an average age of 72.6 (61-76) years. The mean preoperative CSA of facet cyst was 40.09 mm². In all cases, intraspinal facet cyst resolved within two weeks after LLIF and good clinical results were obtained. The mean CSA of the thecal sac increased from 64.18 mm² preoperatively to 95.72 mm² postoperatively. The mean distance of FJ gap increased from 0.8 (0-1.5) mm preoperatively to 3.1 (0.5-6.0) mm postoperatively.

Conclusions

LLIF may be indicated for intraspinal facet cysts with segmental instability.

Clinical outcomes with endoscopic resection of lumbar extradural cysts

Background

Lumbar extradural cysts may be associated with sciatica-type back and leg pain. The symptoms of clinical pain syndrome from synovial cysts are sometimes difficult to differentiate from those of lumbar disc herniation or spinal canal stenosis and may be identified to be a pain source when visualized endoscopically. The authors analyzed the clinical outcomes with their endoscopic resection to better establish clinical indications and prognosticators of favorable results.

Methods

Two-year Macnab outcomes, VAS scores, and complications were analyzed in a series of 48 patients treated with the endoscopic removal of extradural cyst encountered during routine transforaminal and interlaminar decompression for foraminal and lateral recess stenosis causing lumbar radiculopathy.

Results

There were 26 female and 22 male patients. The extradural cysts were most commonly encountered at L4/5 level in 26 patients (72.2%) followed by the L5/S1 level in 8 patients (22.2%), and in 2 patients (5.6%) at the L3/4 level, respectively. One patient underwent T9/10 decompression. At minimum 2-year follow-up, all patients were improved. Excellent results according to the Macnab criteria were obtained in 19/48 (39.6%) patients, good in 18/48 (37.5%), and fair in 11/48 (22.9%), respectively. The average preoperative VAS score for leg pain was 8.06±1.57 and reduced at a statistically significant level (P<0.000) postoperatively to 1.92±1.49, and 1.77±1.32 at final follow-up, respectively. The percentage of patients with unlimited walking endurance had improved at a statistically significant level (P<0.0001) from 33.3% preoperatively (16/48) to 81.3% (39/48) postoperatively. One patient had a recurrent disc herniation, and another patient did not improve. Two patients underwent fusion during the follow-up period. Patients with Fair outcomes had a statistically significant association (P<0.001) with facet instability as suggested by axial T2-weighted magnetic resonance imaging (MRI) findings of thickened ligamentum flavum, facet joint hypertrophy, and bright white fluid-filled joint gap of >2 mm.

Conclusions

Endoscopic resection of extradural spinal cysts during routine decompression for symptomatic foraminal and lateral recess stenosis is feasible with favorable clinical outcomes in the majority of patients. Fair outcomes were associated with advanced instability of the involved lumbar facet joint complex.

The Learning Process of Endoscopic Spinal Surgery for Degenerative Cervical and Lumbar Disorders Using the EasyGO! System

BACKGROUND

Among spinal surgeons, the safety of endoscopic spinal techniques has been criticized as the result of a prolonged learning curve and divergent surgical technique from traditional microsurgery. In this manuscript, the authors assessed the learning curve of 4 experienced microsurgical neurosurgeons in endoscopic spinal surgery.

METHODS

Retrospectively, the surgical reports, the endoscopic video recording, and the files of all patients who underwent an endoscopic procedure for the treatment of cervical and lumbar disc herniation from January 2011 to December 2017 were reviewed. The learning process was assessed via several parameters: surgical time, intraoperative complications, dural tear, nerve root injury, conversion to microsurgery, new postoperative neurologic deficits, repeated procedure, and early recurrent disc herniation.

RESULTS

The learning process of for 4 surgeons was assessed on the basis of 308 procedures. The mean surgical time for the initial procedure ranges from 58 to 97 minutes and improved to 51-85 minutes for the last procedures. A shorter surgical time had no influence on the rate of intraoperative complication and repeated procedure. Increased working space had a significant influence on the surgical time. The number of procedure to reach the asymptote varied from 10 to 20 depending on the endoscopic system and the surgeon.

CONCLUSIONS

The learning process in endoscopic tubular-assisted spinal surgery is variable, and the asymptote might be reached after 10-20 procedures. The amount of working space and instrument angulation affects the surgical time. The decrease of surgical time had no significant influence on the rate of intraoperative complication and repeated procedures.

Current trends in the management of degenerative lumbar spondylolisthesis

Degenerative spondylolisthesis (DS) is a common disease of the degenerative spine, often associated with lumbar canal stenosis. However, the choice between the different medical or surgical treatments remains under debate.

Preference for surgical strategy is based on the functional symptoms, and when surgical treatment is selected, several questions should be posed and the surgical strategy adapted accordingly.

One of the main goals of surgery is to improve neurological symptoms. Therefore, radicular decompression may be necessary. Radicular decompression can be performed indirectly through interbody fusion or interspinous spacer. However, indirect decompression has some limits, and the most frequent technique is a posterior decompression with fusion.

Indeed, in cases of DS, associated fusion or dynamic stabilization are recommended to improve functional outcomes and prevent future destabilization. Risk factors for destabilization, such as anteroposterior and angular mobility, and significant disc height, have been discussed in the literature. When fusion is performed, osteosynthesis is often associated. It is essential to choose the length and position of the fusion according to the pelvic incidence and global alignment of the patient. It is possible to add interbody fusion to the posterolateral arthrodesis to improve graft area and stability, increase local lordosis and open foramina.

The most common surgical treatment for DS is posterior decompression with instrumented fusion. Nevertheless, some cases are more complicated and it is crucial to consider the patient’s general health status, symptoms and alignment when selecting the surgical strategy.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170050

Development of Bilateral Facet Cysts Causing Recurrent Symptoms After Decompression and the Placement of an Intralaminar Implant: A Case Report

CASE

We report the development of bilateral symptomatic facet joint cysts in a 78-year-old man who had been treated with decompression and placement of a coflex device (Paradigm Spine) at L3-L4 and L4-L5. Preoperative imaging clearly demonstrated fluid in the facet joints without cysts. He underwent standard surgical treatment, but developed symptomatic facet joint cysts at 4 months postoperatively. The patient was treated with a revision decompression and replacement of the devices; there were no issues at the 32-month follow-up.

CONCLUSION

While the coflex device has possible long-term biomechanical advantages, vigilance with adherence to appropriate decompression surgical technique is necessary.

Clinical Outcome and Postoperative CT Measurements of Microendoscopic Decompression for Lumbar Spinal Stenosis

STUDY DESIGN

This was a retrospective case series.

OBJECTIVE

To retrospectively evaluate the clinical outcome of microendoscopic decompression for lumbar spinal stenosis (LSS) including an evaluation of the extent of decompression using computed tomography.

SUMMARY OF BACKGROUND DATA

Microendoscopic decompression has been a widely applied procedure to treat LSS with satisfactory outcomes and comparatively fewer complications and revision. However, few reports showed computed tomography (CT) measurements of the lumbar spine to assess the postoperative decompression.

METHODS

This study included 103 patients (55 males and 48 females; mean age, 69 y) who underwent microendoscopic decompression for treatment of LSS between January 2009 and January 2011. All patients underwent preoperative CT and postoperative CT at 6 months and 2 years of follow-up to measure the vertebral canal area and the sagittal diameter of the lateral recess at the outer rim. The Japanese Orthopedic Association (JOA) scale, Oswestry Disability Index, and Visual Analogue Scale were used to evaluate clinical efficacy.

RESULTS

The mean vertebral canal area and sagittal diameter of the lateral recess were significantly larger at 6 months and 2 years after surgery compared with 1 day before surgery (P<0.001). The mean JOA scale scores were significantly higher at 6 and 24 months following surgery compared with before surgery (P<0.001). The mean Oswestry Disability Index scores and Visual Analogue Scale scores at 6 months and 2 years after surgery were significantly lower compared with before surgery (both P<0.001). The mean JOA recovery rates at 6 months and 2 years of follow-up were 61% and 64.3%, respectively.

CONCLUSIONS

The results confirm that microendoscopic decompression for LSS is safe and effective. This study is one of the first to obtain CT measurements of the lumbar spine to assess the postoperative decompression of this procedure.

Surgical treatment of degenerative spondylolisthesis

Degenerative spondylolisthesis is a common pathology, often causing lumbar canal stenosis. There is, however, no strong consensus regarding the various medical and surgical treatments available. Surgery is indicated mainly for perceived functional impairment; when the indication is accepted, several questions determine the choice of surgical strategy. Improvement in neurological symptoms is one of the main treatment objectives. For this, it is useful to perform radicular decompression. Some authors recommend indirect decompression by interbody fusion (ALIF, TLIF, XLIF), others by means of an interspinous spacer but the most frequent technique is direct posterior decompression. In degenerative spondylolisthesis, functional results seem to be improved by associating stabilization to decompression, to prevent secondary destabilization. The following risk factors for destabilization are recognized: anteroposterior hypermobility, angular hypermobility and large disc height. Two stabilization techniques have been described: "dynamic" stabilization and (more frequently) fusion. Spinal instrumentation is frequently associated to fusion, in which case, it is essential for fusion position and length to take account of pelvic incidence and the patient's overall pattern of balance. Posterolateral fusion may be completed by interbody fusion (PLIF or TLIF). This has the theoretic advantage of increasing graft area and stability, restoring local lordosis and opening the foramina. Surgical treatment of degenerative spondylolisthesis usually consists in posterior release associated to instrumented fusion, but some cases can be more complex. It is essential for treatment planning to take account of the patient's general health status as well as symptomatology and global and segmental alignment.

Clinical significance of postdecompression facet joint effusion after minimally invasive decompression for degenerative lumbar spinal stenosis

STUDY DESIGN

A retrospective case series study.

OBJECTIVE

To investigate the clinical significance of postdecompression facet effusion (PDFE) after microendoscopic decompressive laminotomy (MEDL).

SUMMARY OF BACKGROUND DATA

The facet joint effusion noted on magnetic resonance imaging was considered as an indicator of degeneration of the facet joints and segmental instability. PDFE occurring after MEDL might imply postdecompression segmental instability. Its clinical significance has not yet been clarified.

MATERIALS AND METHODS

From 2005 to 2010, 165 patients with degenerative lumbar spinal stenosis (average age: 64.5, average follow-up: 25.8 mo) who received MEDL were reviewed. We investigated the incidence of PDFE with preoperative and repetitive magnetic resonance imaging at 6 months postoperatively. The clinical data and treatment courses were reviewed. The treatment outcomes were evaluated with Oswestry Disability Index and Japanese Orthopedic Association scores.

RESULTS

The incidence of PDFE was 17.0% (n=28), which was significantly higher in patients receiving multilevel decompression and patients with scoliosis or spondylolisthesis. The intensity of low back pain was similar between patients with and without PDFE, but "mechanical" low back pain was only noted in patients with PDFE. Of the 28 patients with PDFE, only 9 symptomatic patients required invasive treatment (5 facet joint steroid injection, 3 revision MEDL, and 1 spinal fusion). Although the postoperative Oswestry Disability Index and Japanese Orthopedic Association scores were significantly worse these 9 patients, the final outcomes were good. Progression of spondylolisthesis was noted in 2 patients without PDFE but no patients with PDFE during the follow-up period.

CONCLUSIONS

The relatively high incidence of PDFE after MEDL suggests that injury to the integrity of facet joint is inevitable during decompression of the stenosis, even using minimally invasive techniques. However, the overall stability is well preserved with very rare progression of spondylolisthesis. Most patients with PDFE are asymptomatic. The prognosis of PDFE is very good. Spinal fusion is rarely indicated.

Microendoscopy-assisted muscle-preserving interlaminar decompression for lumbar spinal stenosis: clinical results of consecutive 105 cases with more than 3-year follow-up

STUDY DESIGN

A retrospective review of data collected prospectively on patients who underwent microendoscopy-assisted muscle-preserving interlaminar decompression (MILD) for lumbar spinal stenosis.

OBJECTIVE

To evaluate the clinical results including surgical invasiveness and reduction rate of facet joint with a follow-up of more than 3 years.

SUMMARY OF BACKGROUND DATA

Hatta et al reported microscopic posterior decompression procedure, MILD for lumbar spinal stenosis with reference to the cervical central approach put forth by Shiraishi. Mikami et al applied spinal microendoscopy to MILD procedure (microendoscopy-assisted MILD).

METHODS

One hundred five consecutive patients, who underwent microendoscopy-assisted MILD, participated in this study. Operative time, blood loss, visual analogue scale (VAS), serum creatine kinase and C-reactive protein, surgical complications, reduction rate of the facet joint, Japanese Orthopaedic Association score, and Short-Form 36 were evaluated.

RESULTS

The operative time was 99.3 minutes and the intraoperative bleeding was 15.7 mL on average. The mean VAS score to assess surgical site pain was 20.6 mm on postoperative day 1. The mean serum creatine kinase on postoperative day 1 and C-reactive protein on postoperative day 3 were 145.4 IU/L and 2.7 mg/dL, respectively. Surgical complications were identified in 2 cases, cauda equina injury and dural tear. The mean reduction rate of the facet joint was 3%. The follow-up rate was 83.3% and the mean follow-up period was 52.7 months. The Japanese Orthopaedic Association score improved significantly from 14.8 to 23.7 points on average. Significant improvements in Short-Form 36 were observed in all subscales except in General Health. Revision surgical procedures were performed in 8 cases at the operated level including 4 of juxtafacet cyst, 3 of disc herniation, and 1 of insufficient decompression.

CONCLUSION

Microendoscopy-assisted MILD is a minimally invasive procedure and favorable clinical results can be expected for lumbar spinal stenosis.

LEVEL OF EVIDENCE

4.

A prospective comparative study of 2 minimally invasive decompression procedures for lumbar spinal canal stenosis: unilateral laminotomy for bilateral decompression (ULBD) versus muscle-preserving interlaminar decompression (MILD)

STUDY DESIGN

A prospective comparative study.

OBJECTIVE

To compare prospectively 2 different types of minimally invasive surgery for lumbar spinal canal stenosis (LSCS): unilateral laminotomy for bilateral decompression (ULBD), and muscle-preserving interlaminar decompression (MILD).

SUMMARY OF BACKGROUND DATA

Although previous studies have reported several procedures of minimally invasive surgery for the treatment of LSCS, no articles prospectively compared 2 different procedures.

METHODS

From 2005 to 2009, we prospectively enrolled 50 patients with LSCS for the treatment with ULBD, and 50 patients for MILD. The patients' symptoms were evaluated using Japanese Orthopedic Association (JOA) score, JOA Back Pain Evaluation Questionnaire, and visual analogue scale before and 2 years after operation. For radiological evaluation, changes in disc height, sagittal translation, and lateral wedging at the decompressed segment, as well as lumbar lordosis were investigated using plain radiographs.

RESULTS

Ninety-nine of 100 patients were followed for a minimum of 2 years. No significant differences were found in the recovery rate of JOA score, improvement of JOA Back Pain Evaluation Questionnaire, and changes of the visual analogue scale between the 2 groups. Radiologically, no significant differences were present in the postoperative degenerative changes in disc height, sagittal translation, and lateral wedging. In multilevel surgical procedures; however, clinical scores in low back pain, and lumbar function were significantly greater in the ULBD group than those in the MILD group. The lateral wedging change at L2-L3 and L3-L4 more frequently occurred in the ULBD group than in the MILD group. On the contrary, the number of patients who demonstrated the postoperative sagittal translation at L4-L5 was significantly greater in the MILD group than in the ULBD group.

CONCLUSION

Both MILD and ULBD were efficacious procedures for improving neurological symptoms in patients with LSCS. In multilevel decompression surgical procedures, ULBD was superior to MILD in terms of improvement of low back pain and lumbar function at the 2-year time point.

LEVEL OF EVIDENCE

3.

Synovial cysts of the cervicothoracic junction causing myelopathy: report of 3 cases and review of the literature

Synovial cysts are uncommon pathological entities in patients with cervical degenerative spinal disease, and there are only a few reports in the literature. Treatment typically involves decompression; however, biomechanical data indicate that laminectomies in the cervical spine also result in cervical instability, specifically within the cervicothoracic junction, supporting the use of fusion as well. The authors describe the use of fusion with decompression in the treatment of 3 patients with cervicothoracic synovial cysts that presented in an acute fashion with associated myelopathy and neurological decline, and they review the diagnostic elements, histopathology, and treatment of these cysts. All 3 of the patients did well with decompression via a posterior approach with a single-level instrumented fusion from C-7 to T-1. Each patient regained complete neurological function and had no residual neurological deficits. These results are promising, although the sample size of 3 cases is too small to make any conclusive evaluations. Future studies incorporating Class I and Class II data are imperative to make firm conclusions regarding general management of this rare entity.

Clinical characteristics of intraspinal facet cysts following microsurgical bilateral decompression via a unilateral approach for treatment of degenerative lumbar disease

PURPOSE

Primary intraspinal facet cysts in the lumbar spine are uncommon, but it is unclear whether cyst incidence increases following decompression surgery and if these cysts negatively impact clinical outcome. We examined the prevalence, clinical characteristics, and the risk factors associated with intraspinal facet cysts after microsurgical bilateral decompression via a unilateral approach (MBDU).

METHODS

We studied 230 patients treated using MBDU for lumbar degenerative disease (133 men and 97 women; mean age 70.3 years). Clinical status, as assessed by the Japanese Orthopedic Association (JOA) score and findings on X-ray and magnetic resonance images, was evaluated prior to surgery and at both 3 months and 1 year after surgery. The prevalence of intraspinal facet cysts was determined and preoperative risk factors were defined by comparing presurgical findings with clinical outcomes.

RESULTS

Thirty-eight patients (16.5%) developed intraspinal facet cysts within 1 year postoperatively, and 24 exhibited cysts within 3 months. In 10 patients, the cysts resolved spontaneously 1 year postoperatively. In total, 28 patients (12.2%) had facet cysts 1 year postoperatively. The mean JOA score of patients with cysts 1 year postoperatively was significantly lower than that of patients without cysts. This poor clinical outcome resulted from low back pain that was not improved by conservative treatment. Most cases with spontaneous cyst disappearance were symptom-free 1 year later. The preoperative risk factors for postoperative intraspinal facet cyst formation were instability (OR 2.47, P = 0.26), scoliotic disc wedging (OR 2.23, P = 0.048), and sagittal imbalance (OR 2.22, P = 0.045).

CONCLUSIONS

Postoperative intraspinal facet cyst formation is a common cause of poor clinical outcome in patients treated using MBDU.

Calcium pyrophosphate dihydrate crystal deposition of multiple lumbar facet joints: a case report

Pseudogout of the lumbar facet joints is rare. We report on a 69-year-old woman with 2-level symptomatic synovial cysts of the facet joints caused by calcium pyrophosphate dihydrate crystal deposition. She underwent surgical decompression for sciatica and low back pain. At one-year follow-up, she had recovered completely.

The microendoscopic decompression of lumbar stenosis: a review of the current literature and clinical results

Lumbar stenosis is a well-defined pathologic condition with excellent surgical outcomes. Empiric evidence as well as randomized, prospective trials has demonstrated the superior efficacy of surgery compared to medical management for lumbar stenosis. Traditionally, lumbar stenosis is decompressed with open laminectomies. This involves removal of the spinous process, lamina, and the posterior musculoligamentous complex (posterior tension band). This approach provides excellent improvement in symptoms, but is also associated with potential postoperative spinal instability. This may result in subsequent need for spinal fusion. Advances in technology have enabled the application of minimally invasive spine surgery (MISS) as an acceptable alternative to open lumbar decompression. Recent studies have shown similar to improved perioperative outcomes when comparing MISS to open decompression for lumbar stenosis. A literature review of MISS for decompression of lumbar stenosis with tubular retractors was performed to evaluate the outcomes of this modern surgical technique. In addition, a discussion of the advantages and limitations of this technique is provided.

Radiological analysis of symptomatic complications after bilateral laminotomy for lumbar spinal stenosis

Objective

The purpose of this study was to describe the various symptomatic complications following decompressive bilateral laminotomy for treating lumbar spinal stenosis.

Methods

Out of 878 patients who underwent decompressive laminotomy from 2006 through 2008, 178 patients who were able to be followed for a minimum of 24 months were included in this study. The mean age at the time of surgery was 64.4 years (range, 38-79), and the average follow-up period was 32.7 months. The development of symptomatic complications was observed using simple radiographs and MR imaging during the follow-up period. Imaging and clinical complications were focused on postoperative spondylolisthesis, disc herniation, and facet cysts, and were analyzed according to developmenttime, the degree of symptom, and their course.

Results

Postoperative simple radiographs revealed that eight out of 178 patients (4.4%) had developed symptomatic spondylolisthesis and six required an interbody fusion procedure. Five patients with disc herniation (2.8%) at the level of the decompressive bilateral laminotomy site underwent another operation within 24 months after the first surgery. In two patients, disc herniations developed within 1 month after surgery. Three (1.7%) out of 178 patients showed facet cysts but all symptoms were relieved by conservative treatment. Spontaneous regression of the cysts was observed during the follow-up period.

Conclusions

Although decompressive bilateral laminotomy for spinal stenosis is believed to effective and reduces the need for fusion, various symptomatic complications were observed after this procedure. It is important to be aware of the possibility for these various complications to improve the surgical outcome.

Degenerative intraspinal cyst of the cervical spine

We describe two cases of degenerative intraspinal cyst of the cervical spine that caused a gradually progressive myelopathy. One case had a cyst that arose from the facet joint and the other case had a cyst that formed in the ligamentum flavum. The symptoms improved immediately after posterior decompression by cystectomy with laminoplasty.

Evidence that atypical juxtafacet cysts are joint derived

OBJECT

Juxtafacet cysts (JFCs) in usual locations have recently been shown to have joint connections. The pathogenesis of JFCs in unusual locations has remained obscure. The authors hypothesize that all JFCs, including atypical ones, are joint derived.

METHODS

In this study the authors sought to explain the occurrence and formation of clinical outliers of spinal JFCs. In Part I, they performed an extensive literature search to identify case reports of spinal intraneural cysts that have been unappreciated despite the fact that they should occur. In Part II, they studied far-lateral (extraforaminal) cysts treated at their institution and reported in the literature. The presence of a joint connection was specifically looked for since this finding has not been widely appreciated.

RESULTS

In Part I, 3 isolated case reports of spinal intraneural JFCs without reported joint connections were identified: 2 involving L-5 and 1, C-8. In Part II, 6 cases involving patients with far-lateral JFCs treated at the authors' institution were reviewed and all 6 had joint connections. Two of these cases had been previously published, although their joint connections were not appreciated. In 2 of the newly reported cases, arthrography confirmed a communication between the facet and the cyst. Only 1 of 5 cases in the literature had a recognized joint connection.

CONCLUSIONS

The authors believe that all JFCs are joint derived. This explanation for intraneural and extraneural JFCs in typical locations would be consistent with the unified articular (synovial) theory and the pathogenesis for intraneural and extraneural ganglion cyst formation in the limbs. Facet joints appear no different from other synovial joints occurring elsewhere. Understanding the pathogenesis of these cysts will help target treatment to the joint, improve surgical outcomes, and decrease recurrences.