Huge thoracolumbar extradural arachnoid cyst excised by recapping T-saw laminoplasty

Background context

Spinal extradural arachnoid cysts are rare expanding lesions in the spinal canal. Total removal of the cyst and repair of the dural defect is the primary treatment for symptomatic spinal extradural arachnoid cysts.

Purpose

To report the usefulness of recapping T-saw laminoplasty in treating huge extradural arachnoid cyst.

Study design

Case report.

Methods

We report the case of a 43-year-old man who presented with a 2-year history of progressive muscle weakness and numbness of the lower extremities. Magnetic resonance imaging (MRI) showed a huge extradural arachnoid cyst at the T12–L3 level extending into bilateral neural foramina and severe posterior compression of the spinal cord and cauda equina.

Results

The patient underwent total resection of the cyst and closure of the communication. En bloc recapping T-saw laminoplasty of T12–L2 including the T12–L1 and L1–L2 facet joints was performed to obtain extensive exposure and preserve posterior stability. Postoperatively, the patient achieved complete recovery of neurologic functions. Follow-up MRI demonstrated no recurrence of the cyst. Bone union after laminoplasty was obtained within 6 months.

Conclusion

Total resection of the cyst and closure of the communication is curative for this rare lesion. Recapping T-saw laminoplasty provides extensive exposure for removal of a large cyst while allowing complete preservation of the posterior spinal elements.     

Chronic expanding hematoma after spinal surgery

Background context

Chronic expanding hematoma after spinal surgery is extremely rare, with no case previously reported in the literature.

Purpose

To report a rare case of a chronic expanding hematoma of the spine that occurred 24 years after thoracic laminectomy and spinal cord tumor resection.

Study design

Case report.

Methods

A 71-year-old man presented with a spinal mass located approximately at the level of the sixth thoracic vertebral body. The patient had undergone thoracic laminectomy with tumor resection 24 years previously. The mass had appeared 5 years after this and had gradually enlarged over 19 years.

Results

The tumor was resected en bloc. The lamina and spinous processes had been partially eroded by the tumor at the fifth and sixth thoracic vertebrae, but the dura was intact. Histopathologic examination confirmed the diagnosis of chronic expanding hematoma. The hematoma had not recurred at the 1-year follow-up.

Conclusion

We report herein an extremely rare case of chronic expanding hematoma after spinal surgery. This entity may be considered a late complication after surgery regardless of the number of years that have passed since the index surgery.     

Influence of an auxiliary facet system on intervertebral discs and adjacent facet joints

Background context

Facet supplementation stabilizes after facetectomy and undercutting laminectomy. It is indicated in degenerative spondylolisthesis with moderate disc degeneration and dynamic stenosis.

Purpose

To determine the influence of an auxiliary facet system (AFS) on the instrumented disc, adjacent levels' discs, and facet joints and to compare it with fusion.

Study design

Finite element study.

Methods

L3–L4, L4–L5, and L5–S1 were studied using a validated finite element model with prescribed displacements for an intact spine, lesion by facetectomy and undercutting laminectomy, AFS, and fusion at L4–L5. The distribution of segmental range of motion (ROM) and applied moments, von Mises stress at the annulus, and facet joint contact forces were calculated with rotations in all planes. Institutional support for implant evaluation and modeling was received by Clariance.

Results

In flexion-extension and lateral bending, fusion decreased L4–L5 ROM and increased adjacent levels' ROM. Range of motion was similarly distributed with intact lesion and AFS. In axial rotation, L4–L5 ROM represented 33% with intact, 55% after lesion, 25% with AFS, and 21% with fusion. Fusion increased annulus stress at adjacent levels in flexion-extension and lateral bending, but decreased stress at L4–L5 compared with AFS. In axial rotation, von Mises stress was similar with fusion and AFS. Facet loading increased in extension and lateral bending with fusion. It was comparable for fusion and AFS in axial rotation.

Conclusions

This study suggests that the AFS stabilizes L4–L5 in axial rotation after facetectomy and undercutting laminectomy as fusion does. This is because of the cross-link that generates an increased annulus stress in axial rotation at adjacent levels. With imposed displacements, without in vivo compensation of the hips, the solicitation at adjacent levels' discs and facet joints is higher with fusion compared with AFS. Fusion decreases intradiscal stress at the instrumented level.     

Long-term follow-up of a case of aneurysmal bone cyst in the lumbar spine

Background context

Aneurysmal bone cyst (ABC) in the spine is relatively rare, so little is known about the natural history of the disease.

Purpose

The purpose of this study was to describe a spinal ABC that was followed for an extended period from lesion enlargement to spontaneous regression.

Study design

Case report.

Methods

A 63-year-old woman had a 1-year-long history of mild low back and bilateral leg pain without any significant neurologic deficits caused by lumbar spinal stenosis. At her first visit to our hospital, magnetic resonance imaging (MRI) showed a small cystic lesion on the left side of the L5 vertebral body. The patient's clinical symptom progression and MRI and computed tomography evaluations were reported for >13 years.

Results

After 6 years, the cystic lesion enlarged significantly and extended into the left pedicle and transverse process of the L5 vertebra. The lesion was diagnosed as an ABC based on multilocular cysts with fluid-fluid levels on MRI and bony septations on computed tomography. Thirteen years after the first visit, the lesion regressed spontaneously without a clear reason, such as biopsy or fracture, and most of the lesion was replaced by fatty marrow. The patient's symptoms stabilized without neurologic deterioration during the follow-up period.

Conclusions

Although spinal ABC is an expandable cystic lesion, we should consider that such a lesion in an elderly patient could spontaneously regress.     

Does catastrophic midline failure of upper thoracic lamina screws violate the spinal canal? A cadaveric biomechanical analysis using two lamina screw techniques

Background context

Lamina screws have been reported to be a biomechanically sound alternative to pedicle screws in the proximal thoracic spine. However, concerns have been raised that midline failure may result in a spinal canal breach.

Purpose

To evaluate the catastrophic failure of proximal thoracic lamina screws using two techniques for lamina screw purchase.

Study design

Biomechanical study with human cadaveric vertebrae.

Patient sample

Not applicable.

Outcome measures

Not applicable.

Methods

Nineteen fresh-frozen T1–T2 vertebrae were Dual energy X-ray absorptiometry scanned for bone mineral density. Caliper measurements of lamina thickness and lateral mass width for bicortical purchase were obtained. Ten specimens had right-to-left 26-mm lamina screws inserted entirely within the length of the lamina (unicortical). Nine specimens had right-to-left 42-mm lamina screws inserted as to extend the length of the lamina and breach the cortex behind the first and second ribs (bicortical). All screws were placed by experienced spine surgeons under fluoroscopic visualization using 4.5-mm cervicothoracic screws. Insertional torque was recorded while placing all implants and reported in “in-lbs.” Tensile loading to failure was performed with the force oriented in the parasagittal plane along the vertebral midline. Pullout loading was applied at a rate of 0.25 mm/s using an MTS 858 MiniBionix II System (MTS Systems, Inc., Minneapolis, MN, USA) with the maximum pullout strength (POS) recorded in Newtons. Video fluoroscopy was performed during midline pullout to evaluate screw failure and ascertain spinal canal breach. After testing, all specimens were visually inspected for spinal canal breach.

Results

Neither the unicortical nor the bicortical lamina screws violated the spinal canal during catastrophic midline failure. The ventral lamina cortex remained intact for both the lamina screw techniques. All of the unicortical lamina screws resulted in dorsal avulsion of the spinous process and lamina. All nine bicortical lamina screws separated the dorsal lamina from the ventral but were able to maintain lateral mass purchase. The peak insertional torque for both lamina screw techniques was not significantly different (p=.20). However, bicortical lamina screw POS (584.8±150.2 N) was significantly greater than unicortical lamina screw POS (455.6±100.2 N) (p=.04). Bone mineral density showed a moderate correlation with unicortical (r=0.67) and bicortical (r=0.47) lamina screw POS.

Conclusion

Our results suggest that catastrophic midline failure of lamina screws does not violate the spinal canal. Of the two techniques tested, bicortical lamina screws have a biomechanical advantage. Lamina screws present a viable option for instrumenting the proximal thoracic spine.     

Psychometric properties of selected tests in patients with lumbar spinal stenosis

Background context

The psychometric properties of many outcome tools commonly used with patients with lumbar spinal stenosis have yet to be examined.

Purpose

Examine the test-retest reliability, responsiveness, and minimum levels of detectable and clinically important differences for several outcome measures in a cohort of patients with lumbar spinal stenosis.

Study design/setting

Cohort secondary analysis of a randomized clinical trial of patients with lumbar spinal stenosis receiving outpatient physical therapy.

Patient sample

Fifty-five patients (mean age, 69.5 years; standard deviation, ±7.9 years; 43.1% females) presenting with lumbar spinal stenosis to physical therapy.

Outcome measures

The Modified Oswestry Disability Index, Modified Swiss Spinal Stenosis Scale (SSS), Patient Specific Functional Scale, and Numeric Pain Rating Scale (NPRS).

Methods

All patients completed the Oswestry Disability Index, SSS, Patient Specific Functional Scale, and NPRS at the baseline examination and at a follow-up. In addition, patients completed a 15-point Global Rating of Change at follow-up, which was used to categorize whether patients experienced clinically meaningful change. Changes in the Oswestry Disability Index, SSS, Patient Specific Functional Scale, and NPRS were then used to assess test-retest reliability, responsiveness, and minimum levels of detectable and clinically important differences.

Results

The Oswestry Disability Index was the only outcome measure to exhibit excellent test-retest reliability with an intraclass correlation coefficient of 0.86 (95% confidence interval, 0.63–0.93). All others ranged between fair and moderate. The Oswestry Disability Index, SSS, and Patient Specific Functional Scale exhibited varying levels of responsiveness, each of which was superior to the NPRS. The minimal clinically important difference for the Oswestry Disability Index was five points, the SSS was 0.36 and 0.10 for symptoms subscale and functional subscale, respectively, 1.3 for the Patient Specific Functional Scale, and for the NPRS, 1.25 for back/buttock symptoms and 1.5 for thigh/leg symptoms.

Conclusions

The results of our study indicate that the Oswestry Disability Index, SSS, and Patient Specific Functional Scale possess adequate psychometric properties to be used in the outcome assessment of patients with lumbar spinal stenosis. However, further investigation is needed to validate these findings in other samples of patients with lumbar spinal stenosis and nonspecific low back pain.     

Acute epidural lipedema: a novel entity and potential complication of bone morphogenetic protein use in lumbar spine fusion

Background context

Bone morphogenetic proteins (BMPs) induce osteogenesis, making them useful for decreasing time to union and increasing union rates. Although the advantages of BMP-2 as a substitute for iliac crest graft have been elucidated, less is known about the safety profile and adverse events linked to their use in spinal fusion. An accumulation of reactive edema in the epidural fat may lead to neural compression and significant morbidity after lumbar spinal fusion. Bone morphogenetic protein has never been implicated as a cause of spinal epidural lipedema.

Purpose

We report on a case of rapid accumulation of edematous adipose tissue in the epidural space after lumbar spine decompression and fusion with bone morphogenic protein.

Study design

Case report.

Methods

The patient was a 45-year-old woman with chronic back pain, worsening bilateral L5 radiculopathy, and degenerative disc disease. Surgery consisting of a one-level transpedicular decompression, transforaminal lumbar interbody fusion, and posterolateral fusion was performed using BMP-2 as an adjunct for arthrodesis.

Results

Two days postoperatively, the patient developed progressive cauda equina syndrome. Lumbar magnetic resonance imaging revealed edematous epidural fat extending above the initial laminectomy, compromising the spinal canal, and compressing the thecal sac. Emergent laminectomies at L3, L4, and L5 were performed, and intraoperative pathology revealed edematous epidural adipose tissue. The patient's cauda equina syndrome resolved after spinal decompression and the removal of epidural fat. Final cultures were negative for infection, and histology report yielded an accumulation of edematous fibroadipose tissue.

Conclusions

We present a case of rapid accumulation of edematous adipose tissue causing cauda equina syndrome after a lumbar decompression and fusion surgery. The acute nature and extensive development of the lipedema presented in this case indicate an intense inflammatory reaction. We hypothesize that there may be a link between the use of BMP-2 and the accumulation of this edematous tissue. A thorough understanding of the mechanisms of BMP-2 and specific guidelines for their role in spinal surgery may improve functional outcomes and reduce the number of preventable complications. To the best of our knowledge and after a thorough literature search, this is the only reported case of epidural lipedema causing cauda equina syndrome.     

Intramedullary arachnoid cyst in association with cervical spondylosis: case report

Background context

Intramedullary spinal arachnoid cysts are considered to be very rare, and only 11 cases have been reported previously. Development of such a cyst in association with marked cervical spondylosis has not been reported until recently.

Purpose

Brief review of reported cases and debate on likely treatment strategy when such a cyst is associated with symptomatic spondylosis.

Study design

To report the first example of a cervicothoracic intramedullary arachnoid cyst along with a symptomatic cervical spondylosis.

Methods

Evaluation of quadriparesis in a 58-year-old female resulted in detection of a cervical spondylotic stenosis that was accompanied with an intramedullary cystic lesion. Parallel management of both pathologies was through a wide laminectomy extending from the lower edge of C3 to T2 with subsequent fenestration and partial resection of the cyst wall via an appropriate dorsal entry root zone myelotomy. Cervicothoracic instrumentation from C3 down to T2 was done to prevent postlaminectomy deformity.

Result

Histopathological findings were consistent with the diagnosis of arachnoid cyst. Postoperatively, the patient exhibited marked improvement in neurologic status.

Conclusion

Through the review of the current case, first example from the literature, we concluded that surgery should target toward the proper management of both pathologies in a single-stage operation.     

A novel MRI classification system for congenital functional lumbar spinal stenosis predicts the risk for tandem cervical spinal stenosis

Purpose

The purpose of this study was to develop a simple and clinically useful morphological classification system for congenital lumbar spinal stenosis using sagittal MRI, allowing clinicians to recognize patterns of lumbar congenital stenosis quickly and be able to screen these patients for tandem cervical stenosis.

Methods

Forty-four subjects with an MRI of both the cervical and lumbar spine were included. On the lumbar spine MRI, the sagittal canal morphology was classified as one of three types: Type I normal, Type II partially narrow, Type III globally narrow. For the cervical spine, the Torg-Pavlov ratio on X-ray and the cervical spinal canal width on MRI were measured. Kruskal–Wallis analysis was done to determine if there was a relationship between the sagittal morphology of the lumbar spinal canal and the presence of cervical spinal stenosis.

Results

Subjects with a type III globally narrow lumbar spinal canal had a significantly lower cervical Torg-Pavlov ratio and smaller cervical spinal canal width than those with a type I normal lumbar spinal canal.

Conclusion

A type III lumbar spinal canal is a globally narrow canal characterized by a lack of spinal fluid around the conus. This was defined as “functional lumbar spinal stenosis” and is associated with an increased incidence of tandem cervical spinal stenosis.

     

Effects of noxious stimulation and pain expectations on neuromuscular control of the spine in patients with chronic low back pain

Background context

Alterations of the neuromuscular control of the lumbar spine have been reported in patients with chronic low back pain (LBP). During trunk flexion and extension tasks, the reduced myoelectric activity of the low back extensor musculature observed during full trunk flexion is typically absent in patients with chronic LBP.

Purpose

To determine whether pain expectations could modulate neuromuscular responses to experimental LBP to a higher extent in patients with chronic LBP compared with controls.

Study design

A cross-sectional, case-control study.

Patient sample

Twenty-two patients with nonspecific chronic LBP and 22 age- and sex-matched control participants.

Methods

Trunk flexion-extension tasks were performed under three experimental conditions: innocuous heat, noxious stimulation with low pain expectation, and noxious stimulation with high pain expectation. Noxious stimulations were delivered using a contact heat thermode applied on the skin of the lumbar region (L4–L5), whereas low or high pain expectations were induced by verbal and visual instructions.

Outcome measures

Surface electromyography of erector spinae at L2–L3 and L4–L5, as well as lumbopelvic kinematic variables were collected during the tasks. Pain was evaluated using a numerical rating scale. Pain catastrophizing, disability, anxiety, and fear-avoidance beliefs were measured using validated questionnaires.

Results

Two-way mixed analysis of variance revealed that pain was significantly different among the three experimental conditions (F2,84=317.5; p<.001). Increased myoelectric activity of the low back extensor musculature during full trunk flexion was observed in the high compared with low pain expectations condition at the L2–L3 level (F2,84=9.5; p<.001) and at the L4–L5 level (F2,84=3.7; p=.030). At the L4–L5 level, this effect was significantly more pronounced for the control participants compared with patients with chronic LBP (F2,84=3.4; p=.045). Pearson correlation analysis revealed that increased lumbar muscle activity in full flexion induced by expectations was associated with higher pain catastrophizing in patients with chronic LBP (r=0.54; p=.012).

Conclusions

Repeated exposure to pain appears to generate rigid and less variable patterns of muscle activation in patients with chronic LBP, which attenuate their response to pain expectations. Patients with high levels of pain catastrophizing show higher myoelectric activity of lumbar muscles in full flexion and exhibit greater neuromechanical changes when expecting strong pain.     

Reoperation rate after surgery for lumbar spinal stenosis without spondylolisthesis: a nationwide cohort study

Background context

Lumbar spinal stenosis is one of the most common degenerative spine diseases. Surgical options are largely divided into decompression only and decompression with arthrodesis. Recent randomized trials showed that surgery was more effective than nonoperative treatment for carefully selected patients with lumbar stenosis. However, some patients require reoperation because of complications, failure of bony fusion, persistent pain, or progressive degenerative changes, such as adjacent segment disease. In a previous population-based study, the 10-year reoperation rate was 17%, and fusion surgery was performed in 10% of patients. Recently, the lumbar fusion surgery rate has doubled, and a substantial portion of the reoperations are associated with a fusion procedure. With the change in surgical trends, the longitudinal surgical outcomes of these trends need to be reevaluated.

Purpose

To provide the longitudinal reoperation rate after surgery for spinal stenosis and to compare the reoperation rates between decompression and fusion surgeries.

Study design/setting

Retrospective cohort study using national health insurance data.

Patient sample

A cohort of patients who underwent initial surgery for lumbar stenosis without spondylolisthesis in 2003.

Outcome measures

The primary end point was any type of second lumbar surgery. Cox proportional hazards regression modeling was used to compare the adjusted reoperation rates between decompression and fusion surgeries.

Methods

A national health insurance database was used to identify a cohort of patients who underwent an initial surgery for lumbar stenosis without spondylolisthesis in 2003; a total of 11,027 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. After adjusting for confounding factors, the reoperation rates for decompression and fusion surgery were compared.

Results

Fusion surgery was performed in 20% of patients. The cumulative reoperation rate was 4.7% at 3 months, 7.2% at 1 year, 9.4% at 2 years, 11.2% at 3 years, 12.5% at 4 years, and 14.2% at 5 years. The adjusted reoperation rate was not different between decompression and fusion surgeries (p=.82). The calculated reoperation rate was expected to be 22.9% at 10 years.

Conclusions

The reoperation rate was not different between decompression and fusion surgeries. With current surgical trends, the reoperation rate appeared to be higher than in the past, and consideration of this problem is required.     

Reduction of caudal traction force using dural sac opening rather than spinal cord detethering for tethered cord syndrome caused by lipomyelomeningocele: a case report

Background context

A few reports have addressed tethered cord syndrome. Detethering surgery has been performed in these cases because abnormal tension on the spinal cord causes neurologic and urologic symptoms.

Purpose

To discuss the surgical treatment of tethered cord syndrome with the belief that the tension on the cord can be decreased by shifting tethered cord to the dorsal side.

Study design

A patient with tethered cord syndrome was surgically treated by shifting the tethered cord to the dorsal side by harnessing the lumbar lordosis instead of detethering.

Methods

We performed surgery to shift the tethered cord to the dorsal side by harnessing the lumbar lordosis to decrease the tension on the spinal cord.

Results

The tethered cord that was pressed to the ventral side because of a lipoma was shifted dorsally by laminectomy and opening of the dural sac. Pain and numbness were alleviated immediately after surgery.

Conclusions

The method used in the present case, that is, shifting the tethered cord and lipoma to the dorsal side by harnessing the lumbar lordosis instead of detethering, is a viable treatment option for tethered cord syndrome.     

Interrater and intrarater agreements of magnetic resonance imaging findings in the lumbar spine: significant variability across degenerative conditions

Background context

Magnetic resonance imaging (MRI) is frequently used in the evaluation of degenerative conditions in the lumbar spine. The relative interrater and intrarater agreements of MRI findings across different pathologic conditions are underexplored, as most studies are focused on specific findings.

Purpose

The purpose of this study was to characterize the interrater and intrarater agreements of MRI findings used to assess the degenerative lumbar spine.

Study design

A retrospective diagnostic study at a large academic medical center was undertaken with a panel of orthopedic surgeons and musculoskeletal radiologists to assess lumbar MRIs using standardized criteria.

Patient sample

Seventy-five subjects who underwent routine lumbar spine MRI at our institution were included.

Outcome measures

Each MRI study was assessed for 10 lumbar degenerative findings using standardized criteria. Lumbar vertebral levels were assessed independently, where applicable, for a total of 52 data points collected per study.

Methods

T2-weighted axial and sagittal MRI sequences were presented in random order to the four reviewers (two orthopedic spine surgeons and two musculoskeletal radiologists) independently to determine interrater agreement. The first 10 studies were reevaluated at the end to determine intrarater agreement. Images were assessed using standardized and pilot-tested criteria to assess disc degeneration, stenosis, and other degenerative changes. Interrater and intrarater absolute percent agreements were calculated. To highlight the most clinically important MRI disagreements, a modified agreement analysis was also performed (in which disagreements between the lowest two severity grades for applicable conditions were ignored). Fleiss kappa coefficients for interrater agreement were determined.

Results

The overall absolute and modified interrater agreements were 76.9% and 93.5%, respectively. The absolute and modified intrarater agreements were 81.3% and 92.7%, respectively. Average Fleiss kappa coefficient was 0.431, suggesting moderate overall agreement. However, when stratified by condition, absolute interrater agreement ranged from 65.1% to 92.0%. Disc hydration, disc space height, and bone marrow changes exhibited the lowest absolute interrater agreements. The absolute intrarater agreement had a narrower range, from 74.5% to 91.5%. Fleiss kappa coefficients ranged from fair-to-substantial agreement (0.282–0.618).

Conclusions

Even in a study using standardized evaluation criteria, there was significant variability in the interrater and intrarater agreements of MRI in assessing different degenerative conditions of the lumbar spine. Clinicians should be aware of the condition-specific diagnostic limitations of MRI interpretation.     

Improvement in pain after lumbar surgery in cancer patients with mechanical radiculopathy

Background context

Lumbar metastases can result in spinal instability and mechanical radiculopathy, characterized by radicular pain produced by axial loading. This pain pattern represents a definitive symptom of neoplastic instability and may serve as a reliable indication for surgical stabilization.

Purpose

We examined the results of surgical decompression and fixation in the treatment of mechanical radiculopathy.

Study design/setting

A retrospective clinical study.

Patient sample

An internally maintained spine neurosurgery database was queried between February 2002 and April 2010. Patients were identified and deemed eligible for inclusion in this study based on the presence of all the following: metastatic tumor, lumbar surgery, and lumbar radiculopathy.

Outcome measures

Visual analog scale (VAS) of pain and Eastern Cooperative Oncology Group (ECOG) status.

Methods

The Memorial Sloan-Kettering Cancer Center Department of Neurosurgery operative database was queried over an 8-year period to identify all patients with spinal metastases who underwent lumbar surgery. Only patients whose operative indication included mechanical radiculopathy were included. Pre- and postoperative pain was assessed with the VAS of pain, whereas pre- and postoperative performance status was evaluated using the ECOG.

Results

Fifty-five patients were included in the cohort. L2 and L3 were the most common levels involved, and most patients underwent multilevel posterior decompression and instrumented fusion. After surgery, 98% of patients reported pain relief. A significant difference between average pre- and postoperative pain scores was found (p<.01). Overall, 41.5% of patients experienced improvement in their ECOG score postoperatively.

Conclusions

Mechanical radiculopathy in patients with spinal metastases represents a highly reliable surgical indication. Spinal decompression and fixation is an effective treatment for pain palliation in this patient population.     

Epidural abscess and cauda equina syndrome after percutaneous intradiscal therapy in degenerative lumbar disc disease

Background context

Percutaneous intradiscal therapies are gaining popularity as a regenerative treatment option for spinal disc degeneration. The risks, benefits, and possible complications associated with such procedures have been poorly defined. As these procedures are performed with increasing frequency, the likelihood that clinicians will be faced with significant complications also increases.

Purpose

The purpose of this study is to describe a significant complication of a percutaneous intradiscal bone marrow and adipose tissue transplantation for symptomatic lumbar disc degeneration.

Study design

The study design is a case report.

Methods

Two weeks after an injection of adipose cells, bone marrow aspirate and plasma into his L3–L4 and L5–S1 lumbar discs, a 64-year-old patient presented to the emergency room with cauda equina syndrome, fever, and back pain. Magnetic resonance imaging diagnosed L3–L4 disc extrusion, discitis with osteomyelitis, and epidural abscess, resulting in emergency decompressive surgery. An epidural abscess was drained, extruded disc material was removed, and cultures obtained. Five days later, once afebrile on antibiotics, he underwent a definitive interbody arthrodesis and stabilization.

Results

Cauda equina syndrome resolved, osteomyelitis (methicillin-resistant Staphylococcus epidermidis) was treated, and instrumented arthrodesis stabilized the involved segment.

Conclusions

Complications associated with the intradiscal injection of agents, such as stem cells, fibrin glue, adipose tissue, or bone marrow, have been poorly defined. Given the nature of the degenerating disc, serious adverse events, including discitis, osteomyelitis, and extrusion of disc contents, may occur.     

Postoperative spinal deformity after treatment of intracanal spine lesions

Background context

Surgical treatment of intracanal (both intramedullary and extramedullary) spine lesions requires posterior decompressive techniques in nearly all instances. Postoperative spinal deformities, most notably sagittal and coronal decompensation, are of significant concern for both the patient and the spinal surgeon.

Purpose

To review and define principles and features of spinal deformities after posterior spinal decompression for intracanal spinal lesions, and to define patients who may benefit from the concomitant spinal fusion.

Methods

A systematic review of MEDLINE was conducted, including articles published between 1980 and 2011. Articles related to spinal deformities after posterior decompression for the treatment of intracanal spine lesions were identified.

Results

Ten articles met all inclusion and exclusion criteria. All were case series with limited evidence (Level IV). Many risk factors to deformity were implied but with limited evidence. Young age was the most commonly identified risk in these articles.

Conclusions

Spinal deformity after posterior decompression is a common complication, most notably in children and young adults, after the removal of intramedullary tumors. Many risk factors have been implied to increase the postoperative development of spinal deformity, including young age, laminectomy extension, preoperative deformity, and extensive facet resection, among others. However, there is a lack of high-quality evidence to propose an algorithm for treatment or preventive measures. New studies with larger series of patients and standardized clinical outcomes are necessary to establish optimal treatment protocols.     

Comparative in-hospital morbidity and mortality after revision versus primary thoracic and lumbar spine fusion

Background context

Despite increasing utilization of surgical spine fusions, a paucity of literature addressing perioperative complications after revision posterior spinal fusion (RPSF) versus primary posterior spine fusion (PPSF) of the thoracic and lumbar spine exists.

Purpose

To examine demographics of patients undergoing PPSF and RPSF of the thoracic and lumbar spine, assess the incidence of perioperative morbidity and mortality, and determine independent risk factors for in-hospital death.

Study design/setting

Analysis of nationally representative data collected for the National Inpatient Sample (NIS).

Patient sample

All discharges included in the NIS with a procedure code for posterior thoracic and lumbar spine fusion from 1998 to 2006.

Outcome measures

In-hospital mortality and morbidity.

Methods

Data collected for each year between 1998 and 2006 for the NIS were analyzed. Discharges with a procedure code for thoracic and lumbar spine fusion were included in the sample. The prevalence of patient- as well as health care–related demographics was evaluated by procedure type (primary vs. revision). Frequencies of procedure-related complications and in-hospital mortality were analyzed. Independent predictors for in-hospital mortality were determined.

Results

We identified 222,549 PPSF and 12,474 RPSF discharges between 1998 and 2006. Patients undergoing PPSF were significantly younger (51.23 years; confidence interval [CI]=51.16, 51.31) and had lower average comorbidity indices (0.40; CI=0.39, 0.41) than those undergoing RPSF (52.69 years; CI=52.43, 52.97) and (0.44; CI=0.43, 0.45), p<.0001. The incidence of procedure-related complications was 16.02% among RPSF compared with 13.44% in PPSF patients (p<.0001). In-hospital mortality rates after PPSF were approximately twice those of RPSF (0.28% vs. 0.15%, p=.006). Adjusted risk factors for increased in-hospital mortality included PPSF compared with RPSF, male gender, and increasing age. A number of comorbidities, complications, and specific surgical indications increased the risk for perioperative death.

Conclusion

Despite being performed in generally younger and healthier patients and having lower perioperative morbidity, PPSF procedures are associated with increased mortality compared with RPSF procedures. The findings of this study can be used for risk stratification, accurate patient consultation, and hypothesis formation for future research.     

Dorsal root ganglion electrical stimulation promoted intertransverse process spinal fusion without decortications and bone grafting: a proof-of-concept study

Background context

Periosteum, endosteum, and bone are innervated by sensory nerves expressing calcitonin gene-related peptide (CGRP), which is a known osteoanabolic peptide and plays an important role in fracture healing and spinal fusion. Synthesis and release of CGRP are found in sensory neurons located in the dorsal root ganglions (DRGs) and can be upregulated by electrical stimulation (ES) at DRG.

Purpose

To prove our study hypothesis on the potential of precise ES at DRG through implantable microelectrical stimulation system (IMESS) for its effect on promoting spinal fusion in a rat model without decortications and bone grafting.

Study design

An experimental animal study.

Methods

A novel IMESS was developed for stimulating L4–L6 DRG in rats. Sixteen rats were used and divided equally into the control group without ES and the ES group, with a daily 20 minutes ES to DRG for 6 weeks. At the end of 6 weeks, radiography and microcomputed tomography were conducted to evaluate new bone formation and spinal fusion. Bilateral L4–L6 DRGs were harvested for immunohistochemistry and quantification of neurons with upregulated CGRP expression.

Results

In the ES group, rate of radiographic fusion with complete and uninterrupted bony bridging was 100% (8/8) at the right L4/L5 transverse processes and 75% (6/8) at the right L5/L6 transverse processes. Bony callus formation was absent at the left L4–L6 transverse processes in the ES group and in bilateral L4–L6 transverse processes in the control group.

Conclusions

We proved for the first time that precise ES at DRG through IMESS effectively promoted intertransverse process fusion in rat model without decortications and bone grafting. Electrical stimulation at DRG might be an attractive minimal invasive bioengineering approach and an alternative therapy for intertransverse process fusion that is increasingly being used for the treatment of degenerative spine disorders.     

Thirty-day readmissions after elective spine surgery for degenerative conditions among US Medicare beneficiaries

Background context

Readmissions within 30 days of hospital discharge are undesirable and costly. Little is known about reasons for and predictors of readmissions after elective spine surgery to help plan preventative strategies.

Purpose

To examine readmissions within 30 days of hospital discharge, reasons for readmission, and predictors of readmission among patients undergoing elective cervical and lumbar spine surgery for degenerative conditions.

Study design

Retrospective cohort study.

Patient sample

Patient sample includes 343,068 Medicare beneficiaries who underwent cervical and lumbar spine surgery for degenerative conditions from 2003 to 2007.

Outcome measures

Readmissions within 30 days of discharge, excluding readmissions for rehabilitation.

Methods

Patients were identified in Medicare claims data using validated algorithms. Reasons for readmission were classified into clinically meaningful categories using a standardized coding system (Clinical Classification Software).

Results

Thirty-day readmissions were 7.9% after cervical surgery and 7.3% after lumbar surgery. There was no dominant reason for readmissions. The most common reasons for readmissions were complications of surgery (26%–33%) and musculoskeletal conditions in the same area of the operation (15%). Significant predictors of readmission for both operations included older age, greater comorbidity, dual eligibility for Medicare/Medicaid, and greater number of fused levels. For cervical spine readmissions, additional risk factors were male sex, a diagnosis of myelopathy, and a posterior or combined anterior/posterior surgical approach; for lumbar spine readmissions, additional risk factors were black race, Middle Atlantic geographic region, fusion surgery, and an anterior surgical approach. Our model explained more than 60% of the variability in readmissions.

Conclusions

Among Medicare beneficiaries, 30-day readmissions after elective spine surgery for degenerative conditions represent a target for improvement. Both patient factors and operative techniques are associated with readmissions. Interventions to minimize readmissions should be specific to surgical site and focus on high-risk subgroups where clinical trials of interventions may be of greatest benefit.