Recapping T-saw laminoplasty for spinal cord tumors

Long-term Follow-up Results of Reconstructive Laminoplasty With L-shaped Leibinger Mini-plate for Posterior Approach in the Treatment of Intraspinal Tumor Surgery

OBJECTIVE

Laminoplasty using mini-plates is one of the most common surgical techniques in surgery for intraspinal pathologies. However, limited are present in the literature. The aim of this study was to determine its long-term clinical and radiologic outcome, specifically using an L-shaped mini-plate.

METHODS

Patients who underwent surgery for spinal intradural pathology from January 2008 to December 2019 were retrospectively reviewed. Those who received laminoplasty using the Leibinger mini-plate and were followed for more than 2 years were included. Patient demographics and clinical and radiographic data were reviewed and analyzed. A total of 117 patients (male:female = 47:70; mean age 50.9 years, range 16-92 years) were included, and mean follow-up period was 50.3 months (range 24-151 months).

RESULTS

The most common pathology was schwannoma (n = 66, 56.4%) followed by meningioma (n = 30, 25.6%). Gross total resection was achieved in 82.9% (n = 97). Clinical outcomes at last follow-up were mostly good and excellent (n = 95, 81.2%). Computed tomography at the postoperative 1-year follow-up were available in 32 patients (27.4%) and the overall fusion rate was 89.3% (50 of 56 laminae). The fusion rate was significantly lower in the cervical spine compared to other locations (50% vs. thoracic [100%], lumbar [85.7%], P < 0.002). No displacement of laminae or postoperative spinal deformity were observed throughout the follow-up.

CONCLUSIONS

Laminoplasty using L-shape Leibinger mini-plates had an 89.3% fusion rate, and no displacement of the re-attached laminae was observed. We think it is a safe and feasible option in surgeries for intraspinal pathologies.

Paraplegia due to spinal epidural lipoma without spinal dysraphism in an adolescent patient: a case report

We report the case of a rare lipoma arising in the epidural space of a 14-year-old boy without spinal dysraphism. Lipomas are rare in pediatric soft tissue tumors, accounting for only about 4% of cases. The incidence of an intraspinal epidural lipoma without spinal dysraphism is extremely rare in pediatric patients. In this case, the patient had progressive motor deficits in the lower extremities and difficulty in urination and defecation. Magnetic resonance imaging showed an extradural tumor compressing the spinal cord at the T3-T7 level. Because of the progressive neurological deficits, we performed an emergency surgery. The tumor was completely resected en bloc, and histopathology revealed mature adipose tissue with fibrous septa, diagnosed as atypical lipomatous tumor / well-differentiated liposarcoma. The patient fully recovered and there was no tumor recurrence for 6 years since the surgery. However, re-examination using fluorescence in situ hybridization after 6 years of surgery changed the diagnosis to lipoma as no amplification of murine double-minute type 2 oncogene was observed. In liposarcoma, histopathological diagnosis using fluorescence in situ hybridization is mandatory. Our case illustrates that immunohistochemical diagnosis alone can be misleading. Hence, prompt surgery is required for progressive neuropathy.

Clinical Outcomes and Postoperative Radiographic Assessment of Osteoplastic Hemilaminectomy in the Treatment of Lumbar Foraminal Nerve Root Compression

Introduction

Osteoplastic hemilaminectomy for the treatment of lumbar foraminal nerve root compression is a safe technique as the exiting nerve root can be directly observed during neuroforaminal decompression without spinal fusion. Moreover, this procedure allows anatomical reconstruction of the posterior elements. However, there might be a potential risk for the progression of lumbar segmental instability after performing this procedure. This study aimed to review the radiographic and clinical outcomes of osteoplastic hemilaminectomy for the treatment of lumbar foraminal nerve root compression.

Methods

We retrospectively reviewed 51 patients who underwent osteoplastic hemilaminectomy with a minimum follow-up of 2 years. The clinical outcomes were evaluated using the visual analog scale (VAS) for low back pain, leg pain, and numbness and the Japanese Orthopaedic Association (JOA) score. Lumbar segmental instability was evaluated as a radiographic assessment using functional radiography. The mean follow-up period was 65 months.

Results

The preoperative VASs for low back pain, leg pain, and numbness were 46±31, 72±26, and 43±34, respectively, which were improved to 24±23, 19±23, and 19±23, respectively. The JOA score was also improved from 14±5 to 22±4. Three patients (5.9%) were reoperated due to recurrent disc herniation within 2 years following surgery. In addition, three patients (5.9%) developed postoperative lumbar segmental instability but did not require additional surgery.

Conclusions

The current study revealed that 94.1% of the patients who underwent osteoplastic hemilaminectomy achieved a significant improvement in the clinical outcomes and did not require additional surgery within 2 years following the procedure. Over a 5-year follow-up on average, 5.9% of the subjects developed postoperative lumbar segmental instability; however, they have maintained acceptable clinical conditions.

Application of open-door laminoplasty with ARCH plate fixation in cervical intraspinal tumors

BACKGROUND

The open-door laminoplasty is an effective procedure for the treatment of cervical spondylotic myelopathy. However, little information is available about the surgical results of open-door laminoplasty in the treatment of intraspinal tumors. In the present study, we aimed to investigate the clinical effect of open-door laminoplasty with ARCH plate fixation in the treatment of cervical intraspinal tumors.

METHODS

This was a retrospective study. From January 2013 to May 2018, 38 patients (13 males and 25 females, the average age of 44 ± 17 years) with cervical intraspinal tumors underwent open-door laminoplasty with ARCH plate fixation in our hospital. The operation time, blood loss, pre- and postoperative visual analog scale (VAS), and Japanese Orthopedic Association (JOA) scores were determined. To determine the radiographic outcomes, cervical X-ray film and magnetic resonance imaging (MRI) were performed before and after the operation, and cervical X-ray sagittal film was used to measure Cobb angle. The clinical data before and after the operation were compared by t-test.

RESULTS

A total of 38 patients underwent a successful operation and demonstrated primary healing. The average operation time was 113 ± 12 min. The average blood loss was 120 ± 19 mL. All patients were followed up for 26.1 ± 2.8 months, and the final follow-up time was more than 24 months. VAS scores were much better at 24 months after operation compared with those before the operation, which were decreased from 6.1 ± 1.1 to 1.4 ± 0.7 (t = 32.63, P < 0.01). The JOA score was improved from 9.9 ± 1.5 to 15.5 ± 0.6 (t = - 18.36, P < 0.01), and the mean JOA recovery rate was 79% ± 11% at 24 months after the operation. There was no significant difference in Cobb angle between pre-operation and 24 months after the operation, which was 9.8 ± 2.6 and 10.3 ± 3.1 respectively (t = - 0.61, P > 0.05). Neither spinal malalignment on the coronal plane nor displacement of the laminoplasty flap was observed on postoperative cervical X-ray and MRI examinations at the final follow-up.

CONCLUSIONS

Open-door laminoplasty with ARCH plate fixation was a safe and effective surgical approach for the treatment of cervical intraspinal tumors.

A Rare Presentation of Spinal Schwannoma Causing Conus Medullaris Syndrome: A Case Series on Surgical Outcome

Introduction

Spinal schwannoma can occur anywhere along the spinal cord but is predominantly seen in the cervical and thoracic region.It composes mainly of well-differentiated schwann cell and is benign in nature. It is typically seen in the peripheral nerves and is commonly associated with neurofibromatosis. Up to 80% of cases, spinal schwannoma is reported to be intradural in location and 15% of cases have both intradural and extradural components. Spinal schwannoma rarely causes conus medullaris syndrome.

Case Report

In this case series, all three female patients in their 4th and 5th decades of life presented with conus medullaris syndrome. Lower back pain, radiculopathy, lower limb weakness, and urinary incontinence are their main clinical presentation. Magnetic resonance imaging shows a well-defined intradural, extramedullary mass compressing onto the conus medullary region. These patients undergone microscopic assisted excision of the tumor and had remarkably good early outcome despite the advanced presentation of neurological deficit.

Conclusion

Despite the late presentation with significant neurological deficit, surgical excision of spinal schwannomas carries a good prognosis postoperatively due to their benign nature and extramedullary location.

Flipped Reposition Laminoplasty for Excision of Intradural Extramedullary Tumors in the Thoracolumbar Spine: A Case Series of 14 Patients

STUDY DESIGN

A retrospective study was done to assess the outcome of the new technique of flipped reposition laminoplasty for excision of intradural extramedullary (IDEM) spinal tumors of the thoracolumbar region.

PURPOSE

To describe flipped reposition laminoplasty technique and evaluate its outcomes.

OVERVIEW OF LITERATURE

Laminectomy has been the conventional approach for the surgical excision of IDEM spinal tumors, but it has potential postoperative complications. Laminoplasty maintains the posterior arch of the spine and avoids complications seen in Laminectomy, such as instability, epidural scarring, and kyphotic deformity.

METHODS

Fourteen patients (nine females and five males) diagnosed with IDEM tumors of the thoracolumbar region operated between 2016 and 2018 were included in this study. Pathologically, five cases were schwannomas; four cases were meningiomas; two cases were ependymomas; and one case each was lymphoma, neurofibroma, and teratoma. All patients had their neurological deficits documented using the American Spinal Injury Association (ASIA) impairment scale. After completion of all preanesthetic formalities, the patients were operated upon by a single surgeon using the flipped reposition laminoplasty technique. Follow-up was done at 1, 3, 6, and 12 months post operation and yearly thereafter.

RESULTS

The mean age of the patients was 35.28 years (14-65 years), and the mean follow-up duration was 17 months (6-26 months). Two patients were assessed with ASIA grade A neurology, one patient improved to ASIA grade B, whereas the other did not improve. Two patients improved from ASIA grade B to ASIA grade D, and seven patients with ASIA grades C and D improved to ASIA grade E. Fusion at the osteotomy site was seen in 92.85% (13 out of 14) cases on one side within 6 months post operation. Fusion was seen in all the cases within 1 year post operation.

CONCLUSIONS

Flipped reposition laminoplasty is an excellent technique providing adequate exposure and additional stability postoperatively.

Efficacy of Conical Laminoplasty After Thoracic Laminectomy

STUDY DESIGN

Retrospective clinical study.

OBJECTIVE

To evaluate the results of a new method of laminoplasty, referred to as conical laminoplasty.

SUMMARY OF BACKGROUND DATA

In surgery for a thoracic intradural tumor, laminectomy is frequently used for tumor resection. However, laminoplasty may be more effective due to prevention of damage to the posterior elements. This method can be performed as recapping T-saw laminoplasty and conical laminoplasty which we refer.

MATERIALS AND METHODS

After en bloc laminectomy, conical laminoplasty (group C; 21 cases) or recapping T-saw laminoplasty (group R; 17 cases) was performed for patients with thoracic spinal cord tumors. If neither was possible, laminectomy (group L; 16 cases) was performed.

RESULT

The number of laminae removed and Japanese Orthopedic Association recovery rates did not differ significantly among the 3 groups. Sagittal kyphosis significantly worsened at final follow-up in group L, but did not change significantly in groups C and R.

CONCLUSIONS

Conical laminoplasty is particularly useful in a case in which T-saw laminoplasty cannot be performed due to tumor expansion in the canal and ossification of the ligamentum flavum. Conical laminoplasty also preserves the posterior elements, which reduces the risk of worsening of kyphosis postoperatively.

Successful treatment of a diffuse type tenosynovial giant cell tumor in the thoracic spine mimicking spinal metastasis by frozen recapping laminoplasty in a patient with thyroid cancer

PURPOSE

Tenosynovial giant cell tumor of the diffuse type (TGCT-D) involving the spine is rare. Its differential diagnosis includes metastatic disease; however, there have been few reports of spinal TGCT-D mimicking spinal metastasis in patients with a history of malignancy.

METHODS

We report on a 35-year-old woman with a history of papillary thyroid cancer who was diagnosed with TGCT-D of the thoracic spine mimicking spinal metastasis. Preoperative computed tomography (CT) revealed a 1.0 × 1.0-cm lytic bone lesion involving the left T7 vertebral lamina, pedicle, and the T6-7 facet joint; the thoracic spine lesion was markedly fluorodeoxyglucose-avid on positron-emission tomography/computed tomography (PET/CT).

RESULTS

Spinal metastasis was initially suspected given the patient's history of papillary thyroid cancer. Total excision was performed with recapping laminoplasty. The resected lamina was frozen in liquid nitrogen and used as a frozen autograft (frozen recapping laminoplasty) for spinal reconstruction with posterior instrumentation. Histological findings supported a diagnosis of TGCT-D. The patient had no evidence of local recurrence 2 years post-surgery. Bone union was achieved 3 years post-surgery.

CONCLUSIONS

TGCT-D can mimic metastasis in PET/CT and should be included in the differential diagnosis if a lytic lesion affecting the posterior elements of the vertebrae involves the facet joints. CT-guided biopsy is recommended for accurate diagnosis when an occult tumor, such as TGCT, is incidentally detected on PET-CT, even in patients with a history of malignant neoplasm. Frozen recapping laminoplasty is useful for complete resection of a spinal tumor, preventing local recurrence, and preservation of the posterior spinal elements.

Solitary thoracic intramedullary spinal neurofibroma microsurgically extirpated via recapping T-saw laminoplasty

We report the case of a 40-year-old female presenting with back pain that was complicated by a solitary intramedullary spinal cord mass at the T10-11 levels, confirmed by magnetic resonance imaging and computed tomography myelography. Microsurgical en bloc extirpation of the tumor approached through a recapping T-saw laminoplasty of T10 was done, and histopathology findings revealed a diagnosis of neurofibroma. Solitary spinal neurofibroma is one of the rarest tumors involving the spinal cord and is very adherent for the lack of a well-defined capsule, requiring careful dissection under microscope magnification for successful en bloc resection. Recapping T-saw laminoplasty affords both maximal exposure and anatomic reconstruction postextirpation, avoiding most postoperative spinal complications.

Spinous Process-Splitting Hemilaminoplasty for Intradural and Extradural Lesions

Objective

To describe a novel spinous process-splitting hemilaminoplasty technique for the surgical treatment of intradural and posterior epidural lesions that promotes physiological restoration.

Methods

The spinous process was split, the area of the facet lamina junction was drilled, and en bloc hemilaminectomy was then performed. After removing intradural and posterior epidural lesions, we fitted the previously en bloc-removed bone to the pre-surgery same shape, and held it in place with non-absorbable sutures. Surgery was performed on 16 laminas from a total of nine patients between 2011 and 2014. Bony union of the reconstructed lamina was assessed using computed tomography (CT) at 6 months after surgery.

Results

Spinous process-slitting hemilaminoplasty was performed for intradural extramedullary tumors in eight patients and for ossification of the ligament flavum in one patient. Because we were able to visualize the margin of the ipsilateral and contralateral dura, we were able to secure space for removal of the lesion and closure of the dura. None of the cases showed spinal deformity or other complications. Bone fusion and maintenance of the spinal canal were found to be perfect on CT scans.

Conclusion

The spinous process-splitting hemilaminoplasty technique presented here was successful in creating sufficient space to remove intradural and posterior epidural lesions and to close the dura. Furthermore, we were able to maintain the physiological barrier and integrity after surgery because the posterior musculature and bone structures were restored.

En-bloc resection of thoracic calcified meningioma with inner dural layer in recapping T-saw laminoplasty: a case report

Background

In the treatment of spinal cord tumors, complete tumor resection with complete reconstruction of the spine represents the ideal goal. However, for the treatment of heavily calcified spinal meningioma, en-bloc resection of the tumor together with the involved dura at the tumor base through laminectomy is quite difficult. Conventional laminectomy is not wide enough to allow full exposure of such tumors, and postoperative dural defects can cause serious complications.

Case presentation

A 58-year-old Japanese woman presented with a 3-month history of progressive muscle weakness and numbness of the lower extremities. Magnetic resonance imaging (MRI) and computed tomography showed a calcified spinal cord tumor with dural tail sign at the T10-T11 level, severely compressing the spinal cord anterolaterally. The patient underwent en-bloc resection of the tumor with the inner layer of the dura and preservation of the outer layer of the dura through recapping T-saw laminoplasty of T10-T11, including bilateral facet joints. The tumor was histologically diagnosed as meningioma. Postoperatively, the patient achieved complete recovery of neurological functions. Bone union after laminoplasty was obtained within 6 months. Follow-up MRI at 5 years postoperatively demonstrated no recurrence of the tumor.

Conclusion

Resection of spinal meningioma with only the inner layer of dura can minimize postoperative complications, including spinal fluid leakage. Recapping T-saw laminoplasty provides extensive exposure for tumor removal. The combination of these techniques may offer an ideal surgical option for complete resection of spinal meningioma with complete preservation of the posterior spinal elements.

One-piece bone flap osteotomy using thread wire saw for fronto-orbital advancement with distraction osteogenesis in craniosynostosis

PURPOSE

The objectives of this study are to describe our new technique of one-piece bone flap osteotomy for fronto-orbital advancement with distraction osteogenesis in craniosynostosis using a thin, flexible, and safe thread wire saw (the T-saw) and to compare the results with those of classic osteotomy using an osteotome.

METHODS

Initial osteotomy is performed between two pterion burr holes using a craniotome with a guarded footplate. The outer sphenoid wing and lateral orbital rim are separated using a reciprocating saw. Limited dura dissection from inner cortex between burr holes in the pterion and nasion is performed. The T-saw is inserted through the epidural space behind the superior orbital wall between the lateral orbital rim and nasion burr hole; the osteotomy is performed with gentle reciprocating strokes. Dura protection with a malleable retractor is not absolutely necessary.

RESULTS

Five patients underwent one-piece fronto-orbital bone flap osteotomies using a T-saw in 2009-2014. The median age was 26 months (7-132 months), median operation time was 275 min (183-303 min), and median estimated blood loss was 65 mL (20-250 mL). These values did not differ from those of control cases. No complications, including incomplete osteotomy, occurred.

CONCLUSIONS

The T-saw creates an osteotomy as a "one-stroke sketch," so incomplete osteotomy never occurs. The osteotomy can be performed safely without protecting the dura. Osteotomy with T-saw does not negate the advantages of fronto-orbital advancement with distraction osteogenesis, including shorter operative time, less intraoperative bleeding, and fewer complications.

Cervical open-door laminoplasty technique with simple sutures and bone grafts: a single institutional study with 30 consecutive cases

Background

Expansive open-door laminoplasty is widely accepted as a reliable procedure for cervical myelopathy. However, one acknowledged complication is spring-back complication or closure of the door which may result in restenosis of cervical canal and neurologic deterioration. The study aimed for addressing our cervical open-door laminoplasty technique with sutures and bone grafts and subsequently the follow-up outcomes.

Methods

Thirty consecutive patients who underwent open-door laminoplasty with the novel technique were included and followed for minimum 5 years from Jan 2006 to Dec 2007. Anteroposterior diameter (APD) of the vertebral canal of C4 was measured in lateral cervical radiographs. Neurologic scenarios were noted using the Japanese Orthopaedic Association (JOA) scores.

Results

Twenty-five males (83.3%) and five (16.7%) females with an average follow-up of 68 months were enrolled. The preoperative APD was 13.22 mm (±1.15), whereas the postoperative APD increased to 31.23 mm (±2.43) with an expansion ratio of 136.23% (P < 0.05). The JOA score increased from 8.5 preoperatively to 13.45 postoperatively with a recovery rate of 58.2% (P < 0.05). The elevated laminas were maintained open during the follow-up period.

Conclusions

Our technique with sutures and bone graft for laminoplasty is a simple and efficient method for maintaining the decompression of cervical canal and neurologic improvement.

Results of cervical recapping laminoplasty: gross anatomical changes, biomechanical evaluation at different time points and degrees of level involvement

Background

Recapping laminoplasty has become the frequently-used approach to the spinal canal when bone decompression of the vertebral canal is not the goal. However, what changes will occur after surgery, and whether recapping laminoplasty can actually reduce the risk of delayed deformities remains unknown.

Methodology

We designed an animal experiment using a caprine model, and partitioned the animals into in vitro and in vivo surgical groups. We performed recapping laminoplasty on one group and laminectomy on another group. These animals were sacrificed six months after operating, cervical spines removed, biomechanically tested, and these data were compared to determine whether the recapping laminoplasty technique leads to subsequent differences in range of motion. Image data were also obtained before the surgery and when the animals were killed. Besides, we investigated the initial differences in kinetics between recapping laminoplasty and laminectomy. We did this by comparing data obtained from biomechanical testing of in vitro-performed recapping laminoplasty and laminectomy. Finally, we investigated the effect that longitudinal distance has on cervical mechanics. This was determined by performing a two-level recapping laminoplasty, and then extending the laminoplasty to the next level and repeating the mechanical testing at each step.

Principal Findings

There were three mainly morphological changes at the six months after laminoplasty: volume reduction and bone nonunion of the recapping laminae, irregular fibrosis formation around the facet joints and re-implanted lamina-ligamentous complex. In the biomechanical test, comparing with laminectomy, recapping laminoplasty didn’t show significant differences in the immediate postoperative comparison, while recapping laminoplasty demonstrated significantly decreased motion in flexion/extension six months later. Inclusion of additional levels in the laminotomy procedure didn’t lead to changes in immediate biomechanics.

Conclusions

Recapping laminoplasty can’t fully restore the posterior structure, but still reduced the risk of delayed cervical instability in a caprine model.

Application of lamina replantation with ARCH plate fixation in thoracic and lumbar intraspinal tumors

The aim of the present study was to investigate the clinical effects of lamina replantation with ARCH plate fixation on patients with thoracic and lumbar intraspinal tumors, following laminectomy. Thirteen patients with thoracic and lumbar intraspinal tumors underwent total lamina replantation with ARCH plate fixation and repair of the supraspinous ligaments, following laminectomy and tumor enucleation. To investigate the clinical effect of lamina replantation with ARCH plate fixation, pre- and postoperative visual analog scale (VAS), and Oswestry Disability Index (ODI) scores were determined, and pre- and postoperative X-ray and magnetic resonance imaging (MRI) examinations were conducted. Computed tomography (CT) examinations were also included in the follow-up. No complications were observed pre- or postoperatively. The VAS and ODI results 2 weeks following surgery and at the final follow-up examination demonstrated a significant improvement compared with the corresponding preoperative results. The X-ray examination results indicated a satisfactory internal fixation location, without any characteristics of a fracture, lumbar scoliosis, kyphosis or instability. Following the surgery, the CT and MRI examination results demonstrated that healing of the lamina bone and repair of the supraspinous ligament had occurred without tumor recurrence or spinal epidural scar recompression. Two of the 13 cases were lost to follow-up. The results indicated that in patients with thoracic and lumbar intraspinal tumors, lamina replantation with ARCH plate fixation following total laminectomy is effective and provides thoracolumbar stability. Furthermore, this has been identified to be an effective technique for preventing intraspinal scar proliferation.

Publication patterns of comparative effectiveness research in spine neurosurgery

OBJECT

The purpose of this study was to investigate publication patterns for comparative effectiveness research (CER) on spine neurosurgery.

METHODS

The authors searched the PubMed database for the period 1980-2012 using the key words "cost analysis," "utility analysis," "cost-utility," "outcomes research," "practical clinical research," "comparator trial," and "comparative effectiveness research," linked with "effectiveness" and "spine neurosurgery."

RESULTS

From 1980 through April 9, 2012, neurosurgery CER publications accounted for 1.38% of worldwide CER publications (8657 of 626,330 articles). Spine neurosurgery CER accounted for only 0.02%, with 132 articles. The journal with the greatest number of publications on spine neurosurgery CER was Spine, followed by the Journal of Neurosurgery: Spine. The average annual publication rate for spine neurosurgery CER during this period was 4 articles (132 articles in 33 years), with 68 (51.52%) of the 132 articles being published within the past 5 years and a rising trend beginning in 2008. The top 3 contributing countries were the US, Turkey, and Japan, with 68, 8, and 7 articles, respectively. Only 8 regular articles (6.06%) focused on cost analysis.

CONCLUSIONS

There is a paucity of publications using CER methodology in spine neurosurgery. Few articles address the issue of cost analysis. The promotion of continuing medical education in CER methodology is warranted. Further investigations to address cost analysis in comparative effectiveness studies of spine neurosurgery are crucial to expand the application of CER in public health.

Clinical analysis of 73 cases of intraspinal nerve sheath tumor

Seventy-three patients with spinal nerve sheath tumor who were surgically treated in our hospital during the years 2004-2010 were retrospectively reviewed with respect to recovery of neurological function, recurrence of the tumor and occurrence of kyphotic deformities. Preoperative clinical manifestations, imaging data, surgical records and follow-up results were comprehensively analyzed. The follow-up duration was 12-60 months with an average of 32.0 months. Out of the 73 cases enrolled, 69 had gradual recovery of sensation, motor and sphincter functions 1 week to 3 months after operation. Forty-six cases had incomplete paralysis, whose American Spinal Injury Association (ASIA) grades, however, were gradually increased during the follow-up period, 4 cases had no significant improvement of the clinical symptoms and no change in ASIA grades during the follow-up period. Two cases had postoperative recurrence of the tumor. There were no deaths, no spinal instability, and no kyphotic malformations found in any cases. Our study indicated that complete removal of the tumor is important for good recovery, and an ideal surgical method may reduce the recurrence of the tumor or the occurrence of complications.

Microsurgical management of non-neurofibromatosis spinal schwannoma

INTRODUCTION

The aim of this study is to assess the clinical properties and surgical results of patients diagnosed with spinal schwannomas without neurofibromatosis (NF) properties.

PATIENTS AND METHODS

The data obtained from 35 patients who underwent resection of spinal schwannomas were analyzed. All cases with neurofibromas and those with a known diagnosis of NF Type 1 or 2 were excluded. 35 patients underwent surgery for spinal schwannoma at our institution between January 1997 and 2010. The data were gathered retrospectively from medical records and included clinical presentation, tumor location and post-operative complications. All cases were surgically excised, and they were confirmed to be schwannomas by pathologists with histopathological sections in paraffin stained with hematoxylin-eosin.

RESULT

We treated 35 (20 males and 15 females) patients with spinal schwannomas. The mean age of the patients was 47.2 (between 13 and 76) years. Of the cases, six schwannomas were located in the cervical spine, four in the thoracic spine, two in cervico-thoracic area, 10 in the thoraco-lumbar area and 13 in the lumbar spine. Two patients had malignant schwannomas that were recurrent. Of the 35 cases, the schwannomas were intradural-extramedullary in 30 cases (86%), intradural-intramedullar in 2 cases (6%), and extradural in 3 cases (9%).

CONCLUSION

Spinal schwannomas may occur at any level of the spinal axis and are most frequently intradural-extramedullary. The most common clinical presentation is pain. Most of the spinal schwannomas in non-NF patients can be resected completely without or with minor post-operative deficits. This knowledge may help us to create a strategy for total resection of a spinal schwannomas.

A glass foreign body migrating into the lumbar spinal canal: a case report

We report on a 12-year-old boy in whom a glass fragment migrated into the lumbar spinal canal causing low back pain and radiculopathy 6 years after injury. Computed tomography showed a foreign body in the anterior spinal canal of L5/S1. The patient underwent recapping T-saw laminoplasty to remove the foreign body. Scar formation was noted at the anterior dura. The glass fragment seemed to have penetrated into the intradural space from an anterior site. Postoperatively, the pain resolved immediately. At the 9-year follow-up, the alignment of the lumbar spine and healing of L5 was good, with no features of aseptic necrosis.

Repositioning of Cranial Bone Flaps Cut with a Diamond-Coated Threadwire Saw: 5-Year Experience with Cosmetic Cranioplasty without Fixation Devices

Artificial fixation systems for cranial bone flaps have problems related to their materials and designs. We developed an alternative technique for supratentorial craniotomy that employs a diamond-coated threadwire saw (diamond T-saw), originally developed for spinal surgery, and reduces the bone gap for fitted bone flap fixation. The study subjects were 77 adults undergoing elective supratentorial craniotomy. After placing a burr hole at each corner of the craniotomy, we performed osteotomy between adjacent burr holes to approximately one-third of the length of the osteotomy with a craniotome; this leaves a bony bridge at each corner. The diamond T-saw was introduced between adjacent burr holes through the epidural space and a bridge was cut with reciprocating strokes. On closure, the bridge firmly supports the flap and only sutures are needed for fixation. Successful bone flap fixation was obtained in all followed-up cases. There were no technique-related complications such as dural laceration, flap displacement, or resorption. Our method is ideal for bone cuts in cosmetic cranioplasty; it is easy, safe, and inexpensive and avoids the need for flap fixation with artificial devices.

Laminoplasty for the treatment of extramedullary intradural tumors in the thoracic and lumbar spine: greater than two-year follow-up

OBJECTIVE

To investigate the outcome of a laminoplasty technique without additional instrumentation for fixation of laminae in the treatment of extramedullary intradural tumors in the thoracic and lumbar spine.

METHODS

Twenty-four patients (15 men and 9 women) with extramedullary intradural tumors in the thoracic and lumbar spine were included in our study. The average age was 36.2 years (range 18 to 61 years). The pathological diagnosis was neurofibroma in 13, ependymoma in 6, lipoma in 2 and teratoma in 3 cases. All patients underwent the same laminoplasty surgery as follows: the laminae were reattached to their original sites, the ligaments (including the supraspinal, interspinal and yellow ligaments) were conserved, and primary stability of the re-attached laminae was achieved with silk or nylon sutures.

RESULTS

Sixty-six laminae were re-implanted in 24 patients. The average length of follow-up was 34.2 months (26.5 to 41 months). Fusion of the laminae was achieved in a mean of 4.5 months (3 to 6 months). Unilateral healing of the incision lines was observed in seven cases, including one with two-level laminotomy, three with three-level laminotomy and three with four-level laminotomy. The other 17 cases underwent bilateral fusion.

CONCLUSION

Fixing the laminae, spinous processes and ligaments with sutures can achieve satisfactory primary stability and high fusion rates for resected laminae. Additional instrumentation may be necessary in greater than three-level laminoplasty.

"Spring-back" closure associated with open-door cervical laminoplasty

BACKGROUND CONTEXT

Spring-back complication after open-door laminoplasty as described by Hirabayashi is a well-known risk, but its definition, incidence, and associated neurologic outcome remain unclear.

OBJECTIVE

To investigate the incidence and the neurologic consequence of spring-back closure after open-door laminoplasty.

STUDY DESIGN

A retrospective radiographic and clinical review.

OUTCOME MEASURES

Lateral cervical spine X-rays were evaluated. Anteroposterior diameters (APD) of the vertebral canal of C3-C7 were measured. Spring-back was defined as loss of APD on follow-up in comparison to immediate postoperative canal expansion. The loss of the end-on lamina silhouette with consequent reappearance of the lateral profile of the spinous processes was also assessed to verify the presence of spring-back. Spring-back closure was classified based on whether the collapse was total or partial, and whether all the operated levels or only a subset had collapsed (ie, complete vs. partial closure, segmental closure vs. total-construct closure). Neurologic status was documented using the Japanese Orthopaedic Association (JOA) score.

METHODS

Thirty consecutive patients who underwent open-door laminoplasty from 1995 to 2005 at a single institution with a minimum follow-up of 2 years were assessed. They were all operated on using the classic Hirabayashi technique. Radiographic outcomes were assessed independently by two individuals.

RESULTS

Sixteen men and 14 women with an average follow-up of 5 years (range, 2-12 years) were included. Of these patients, 24 had cervical spondylotic myelopathy and six had ossification of the posterior longitudinal ligament. Spring-back closure was found in three patients (10%) and 7 of 117 laminae (6%) within 6 months of the operation, which was further confirmed by computed tomography and magnetic resonance imaging. All spring-back closures were partial segmental closures. Gender and age were not significant factors related to spring back (p>.05). The mean JOA score on follow-up was 12.5, with a recovery rate of 40%. All patients with spring back and available JOA data exhibited postoperative neurologic deterioration. Of the three patients with spring back, two patients underwent revision surgery, whereas one declined.

CONCLUSIONS

Spring-back closure occurred in 10% of our patients at or before 6 months after surgery. The incidence of spring-back by level (ie, 117 laminae) was 6%, mainly occurring at the lower cervical spine. All spring-back closures were partial segmental closures, most commonly involving C5 and C6. Postoperative neurologic deficit was associated with spring-back closure; therefore, surgeons should adopt preemptive surgical measures to prevent the occurrence of such a complication.

Spinal shortening and monosegmental posterior spondylodesis in the management of dorsal and lumbar unstable injuries

Introduction:

Patients with spinal injuries have been treated in the past by laminectomy in an attempt to decompress the spinal cord. The results have shown insignificant improvement or even a worsening of neurologic function and decreased stability without effectively removing the anterior bone and disc fragments compressing the spinal cord. The primary indication for anterior decompression and grafting is narrowing of the spinal canal with neurologic deficits that cannot be resolved by any other approach. One must think of subsequent surgical intervention for increased stability and compressive posterior fusion with short-armed internal fixators.

Aim:

To analyze the results and efficacy of spinal shortening combined with interbody fusion technique for the management of dorsal and lumbar unstable injuries.

Materials and Methods:

Twenty-three patients with traumatic fractures and or fracture-dislocation of dorsolumbar spine with neurologic deficit are presented. All had radiologic evidence of spinal cord or cauda equina compression, with either paraplegia or paraparesis. Patients underwent recapping laminoplasty in the thoracic or lumbar spine for decompression of spinal cord. The T-saw was used for division of the posterior elements. After decompression of the cord and removal of the extruded bone fragments and disc material, the excised laminae were replaced exactly in situ to their original anatomic position. Then application of a compression force via monosegmental transpedicular fixation was done, allowing vertebral end-plate compression and interbody fusion.

Results:

Lateral Cobb angle (T₁₀–L₂) was reduced from 26 to 4 degrees after surgery. The shortened vertebral body united and no or minimal loss of correction was seen. The preoperative vertebral kyphosis averaged +17 degrees and was corrected to +7 degrees at follow-up with the sagittal index improving from 0.59 to 0.86. The segmental local kyphosis was reduced from +15 degrees to −3 degrees. Radiography demonstrated anatomically correct reconstruction in all patients, as well as solid fusion.

Conclusion:

This technique permits circumferential decompression of the spinal cord through a posterior approach and posterior interbody fusion.

Laminotomy in adults: technique and results

The objective of this study was to describe step by step our surgical technique of laminotomy and analyze our series with regard to spinal deformities (risk and predisposing factors), postoperative pain and rate of postoperative contusions. Data regarding patients who underwent our technique of laminotomy (N = 40, mean follow-up: 52 ms) (N = 40) between 2002 and 2006 were retrospectively evaluated. The technique used is illustrated in depth. Chronic pain was present in 30% with a mean score of 3/10 cm (Graphic Rating Scale). Postoperative kyphoses occurred in three patients, all below 35 years of age and with laminotomies which involved C2 and/or C7. None of these deformities required further surgical treatment because they were self-limiting or asymptomatic at a mean follow-up of 52 months. Based on the results, our technique proved to be safe and effective in terms of late deformities, blood loss, early and chronic postoperative pain and protection from postoperative accidents over the surgical site.

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.

Outcome of osteoplastic laminotomy for excision of spinal cord tumours

PURPOSE

To evaluate the outcome of osteoplastic laminotomy after excision of primary tumours of the thoracolumbar and lumbar spine.

METHODS

Records of 10 male and 11 female consecutive patients aged 15 to 57 (mean, 37) years who underwent osteoplastic laminotomy for excision of spinal cord tumours in the thoracolumbar (n=13) and lumbar (n=8) spine were reviewed. After tumour resection, the removed posterior elements were reattached to the superior and inferior processes using anchoring sutures. Pre- and post-operative functional status was retrospectively graded according to the modified McCormick scale. Spinal deformities were classified as sagittal and coronal malalignment, segmental instability, and spondylolisthesis.

RESULTS

The mean follow-up duration was 43 (range, 12-108) months. The mean number of laminae excised was 1.3 (range, 1-4). At the final follow-up, the modified McCormick scale score improved in 16 patients, remained unchanged in 4, and deteriorated in one. No patient developed any severe complication, recurrence, spondylolisthesis, or aseptic necrosis of grafted laminae. In 2 patients their spinal deformities became worse: one had segmental instability of 17 degrees at L3-4 secondary to non-union of the L3 lamina; the other (with type-I neurofibromatosis and dystrophic deformity) underwent fusion for severe low back pain and lumbar kyphosis and progressive rotational dislocation, despite union of the grafted L2 lamina.

CONCLUSIONS

Osteoplastic laminotomy preserves the structures that could be important for spinal stability and may reduce the risk of deformities. Anterior strut grafting and posterior fusion may be necessary in neurofibromatosis patients with dystrophic deformities.

Recapping T-saw laminocostotransversoplasty for ventral meningiomas in the thoracic region

BACKGROUND

Treatment of ventral lesions to the spinal cord in the thoracic spinal canal (e.g., meningiomas) are surgical challenges. Original or modified costotransversectomy has been commonly used for extirpation of such lesions. However, these techniques incur great loss of posterior elements followed by spinal instability that requires spinal fusion. The authors have developed a new surgical technique that combined the advantages of posterolateral exposures and recapping laminoplasty (recapping T-saw laminocostotransversoplasty). The purpose of this study was to examine the safety and effectiveness of this technique for surgical excision of ventrally located meningiomas in the thoracic region.

METHODS

Three patients underwent recapping laminocostotransversoplasty for extirpation of ventral meningiomas in the thoracic spine. A T-saw was used for bone cutting. Following tumor extirpation with the infiltrated dura and dural reconstruction, the resected posterior elements were recapped to their original sites. Patients were evaluated both clinically and radiographically by plain radiography and computed tomography (CT).

RESULTS

Tumor excision, dural reconstruction, and bone recapping were achieved without neurological complications in all patients. Neurological improvement was observed dramatically in all three patients. A mean of 2.3 laminae and 1.3 ribs were excised. The mean follow-up was 9.7 years. CT scans confirmed primary bony union in all patients within 6 months. No major complications were reported.

CONCLUSIONS

Recapping T-saw laminocostotransversoplasty not only provides greater access to the anterior thoracic spinal canal but also allows anatomical reconstruction of the excised bone.

Thoracic and lumbar laminoplasty using a translaminar screw: morphometric study and technique

OBJECT

The aim of this study was to describe a novel technique for laminoplasty in which translaminar screws are used in the thoracic and lumbar spine.

METHODS

The authors first performed a morphometric study in 20 control individuals using 3D reconstructed CT scans and spine simulation software to measure the lengths and diameters of the spaces available for translaminar screw placement from the T-1 to S-1. Based on the results of the morphometric study, the authors then attempted translaminar screw fixation in 5 patients (April 2007-July 2007) after en bloc laminectomy in the thoracic and lumbar regions. All patients had intradural lesions: 3 schwannomas, 1 cavernoma, and 1 arachnoid cyst.

RESULTS

The morphometric study in control individuals revealed that the safe trajectories for simulated screws measured 25-30 mm in length and 8-11 mm in diameter in the thoracic region (T1-12) and 26-34 mm in length and 6-7 mm in diameter in the lumbosacral region (L1-S1). This morphometric and simulation study showed that translaminar screw placement would be possible in practice. Five patients underwent en bloc laminoplasty and translaminar screw fixation in which the screws measured 2.7 mm in diameter and 24 or 26 mm in length. Sixteen attempts at translaminar fixation were made in 8 vertebrae. Fourteen translaminar screws were successfully placed at the thoracic and lumbar levels. Two microplates had to be used because the laminae were too thin and narrow after further laminectomy with undercutting. There were no complications associated with the translaminar screws. The mean follow-up period was 14.5 months. There was no screw breakage or displacement. Solid osseous fusion was documented in 2 patients who underwent CT scanning 15 months postoperatively.

CONCLUSIONS

The authors found that the laminoplasty and translaminar screw technique is feasible in the thoracic and lumbar regions, but further studies are needed to analyze the biomechanical effects and long-term outcomes in a large number of patients.

A color-coded orthotopic nude-mouse treatment model of brain-metastatic paralyzing spinal cord cancer that induces angiogenesis and neurogenesis

OBJECTIVE

Cancer of the spinal cord is highly malignant and often leads to paralysis and death. A realistic mouse model would be an important benefit for the better understanding and treatment of spinal cord glioma.

MATERIALS AND METHODS

To develop an imageable, patient-like model of this disease, U87 human glioma tumour fragments (expressing red fluorescent protein), were transplanted by surgical orthotopic implantation into the spinal cord of nontransgenic nude mice or transgenic nude mice expressing nestin-driven green fluorescent protein (ND-GFP). In ND-GFP mice, GFP is expressed in nascent blood vessels and neural stem cells. The animals were treated with temozolomide or vehicle control.

RESULTS

The intramedullary spinal cord tumour grew at the primary site, caused hind-limb paralysis and also metastasized to the brain. Temozolomide inhibited tumour growth (P<0.01) and prevented metastasis, as well as prevented paralysis in four mice and delayed paralysis in two mice of the six tested (P=0.005). In the ND-GFP-expressing host, ND-GFP cells staining positively for neuronal class III-beta-tubulin or CD31, surrounded the tumour. These results suggest that the tumour stimulated both neurogenesis and angiogenesis, respectively.

CONCLUSION

A patient-like model of spinal cord glioma was thus developed, which can be used for the discovery of new agents, including those that inhibit invasion and metastasis of the disease as well as those that prevent paralysis.

Unilateral partial hemilaminectomy in the removal of a large spinal ependymoma

BACKGROUND CONTEXT

Although the hemilaminectomy technique is known to neurosurgeons performing spinal surgery, laminectomy traditionally has been used during spinal canal surgery for extirpation of spinal cord tumors.

PURPOSE

Although the technique of unilateral partial hemilaminectomy is familiar in its various permutations to surgeons, its application in the spinal tumor surgery has been rarely reported. The aim of this study was to review the literature about the management of spinal cord ependymomas and to discuss the major controversies in treatment.

STUDY DESIGN

Case report.

PATIENT SAMPLE

A 52-year-old man.

METHODS

The 52-year-old man complained of backache and leg pain bilaterally, dominant on the left side. Spinal magnetic resonance images revealed an intradural mass at the T12-L2 level. A left unilateral hemilaminectomy of the T12-L1 and L2 was performed with the help of high-speed air drills under microscopic magnification and a midline incision was made on the dura. The tumor was totally removed.

RESULTS

By using microsurgical techniques and with the help of high-speed drills, a unilateral approach to the intramedullary tumors proved itself to be a safe and easy method in this case. It protected the posterior supporting elements and also permitted the surgeon to manipulate the intradural contralateral side easily. The only difficulty during the operation was the suturing of the dural sac.

CONCLUSIONS

This case report emphasizes the need to consider the hemilaminectomy technique in spinal tumor surgery.

Primary filum terminale ependymoma: a series of 16 cases

Filum terminale ependymomas are slow growing tumors of the cauda equina with a high incidence in young adults. Although a complete microsurgical resection can lead to a cure, recurrence is not uncommon. Sixteen cases of filum terminale ependymomas treated at the Instituto de Neurologia de Curitiba were analyzed. Eleven patients were females and 5 males, their age ranging from 7 to 84 years. Symptoms and signs included lumbar pain (31.25%), radicular pain (56.25%) and neurological deficits (12.5%). In three cases, patients had previously undergone surgery in other hospitals. All were tested through MRI and were operated on. Two underwent a laminoplasty and 14 a laminectomy. The last 8 patients of this series had neuro-physiological monitoring during surgery. In all patients a total microsurgical resection was achieved. Histologically, 2 cases were cellular ependymomas and 14 cases myxopapillary ependymomas. There was no recurrence during a 2 to 84 month follow-up period.

Spinal schwannoma; analysis of 40 cases

OBJECTIVE

This study is to report our experience of 40 cases of spinal schwannoma.

METHODS

From 1995 to 2006, medical records were retrospectively reviewed in 40 cases of spinal schwannoma.

RESULTS

We treated 40 spinal schwannomas in 38 (22 male and 16 female) patients. The mean age was 50.2. Four cases were sited in the cervical spine, 11 cases in the thoracic spine, and 25 cases in the lumbar spine. Two patients showed recurrences. Thirty-eight cases were intradural-extramedullary type and 2 cases were extradural. Two cases (5%) including 1 recurred case had no postoperative motor improvement. Ninety-five percents of patients improved on postoperative motor grade.

CONCLUSION

Spinal schwannoma is mostly benign and extramedullary tumor. There were 2 recurred cases (5%) that had history of previous subtotal removal at first operation and had shown worse prognosis compared with the cases without recurrence. To reduce the recurrence of spinal schannoma, total excision of tumor mass should be done.

Far Lateral Extraforaminal Facet Cyst Causing L5 Radiculopathy

Most synovial cysts of the lumbar spine appear as intraspinal extradural masses adjacent to the facet joint. Almost all symptomatic synovial cysts are located within the spinal canal and or the neural foramen. To our knowledge, only 6 cases of symptomatic extraspinal synovial cysts have been described in the literature. The authors report a case of lumbar radiculopathy caused by a synovial cyst located in the far lateral extraforaminal area. The patient underwent decompression of the L5 nerve root with recapping right isthmectomy and facetectomy. Postoperative recovery was uneventful, and the patient was totally pain free with no motor deficit. Symptomatic synovial cysts are uncommon lesions that are associated with degenerative disease of the spine. Juxtafacet cysts should be considered in the differential diagnosis of space-occupying lesions at the extraforaminal areas. Recapping isthmectomy and facetectomy are useful procedures for a synovial cyst located in the far lateral extraforaminal area.

The transverse placement laminoplasty using titanium miniplates for the reconstruction of the laminae in thoracic and lumbar lesion

Laminoplasty for thoracic and lumbar spine surgery enables surgeons to preserve the posterior arch of the spine while preventing invasion of hematoma and scar tissue, postoperative instability, subluxation, and kyphotic deformities. The authors have developed a new surgical technique: namely, transverse placement laminoplasty (TPL) using titanium miniplates. Eight patients and 18 laminae underwent TPL using a titanium mini-plate. The preoperative diagnoses were six intradural tumors, one ossification of a yellow ligament and one spontaneous spinal cord herniation. The mean blood loss was 219 g and the mean duration of surgery was 3 h and 54 min. The mean postoperative follow-up period was 2 years and 1 month. All eight patients started to sit with a soft brace within the second postoperative day, and were able to walk within the fifth postoperative day. There were no cases of spinal deformity, an invasion of hematoma or scar tissue into the spinal canal on magnetic resonance imaging, or back pain. TPL simultaneously enables surgeons to obtain sufficient field of vision and rigid early fixation of the reduced lamina at the time of surgery. Moreover, our novel technique also simplifies the postoperative treatment, while preserving the posterior arch of the spine, and also preventing an invasion of a hematoma and scar tissue, postoperative instability, subluxation, and kyphotic deformities.

Novel use of a threadwire saw for high sacral amputation

✓ The authors describe and demonstrate an innovative modification of the osteotomy procedure required to achieve a supraforaminal high sacral amputation in a patient harboring a large sacral chordoma. Via a combined anterior—posterior approach, three carefully placed threadwire saws were used to create releasing osteotomies through specific portions of the dorsal iliac crests and through the axial midportion of the S-1 vertebral body. The threadwire saws are pulled away from neurovascular and visceral structures, ensuring greater protection. Other advantages include markedly reduced blood loss while performing the osteotomies, a high degree of cutting accuracy, negligible bone loss, and ease and speed of bone cutting.

Reconstruction of the laminar roof with miniplates for a posterior approach in intraspinal surgery: technical considerations and critical evaluation of follow-up results

STUDY DESIGN

A retrospective clinical follow-up study of patients who underwent intraspinal surgery with reconstruction of the laminar roof using titanium miniplates.

OBJECTIVE

To evaluate the surgical technique of laminar roof reconstruction and to analyze follow-up results with regard to bony healing of the laminae and the development of spinal deformities.

SUMMARY AND BACKGROUND DATA

The reconstruction of the laminar roof was initially proposed to overcome adverse effects associated with extensive cervical laminectomy in children. Because technical evolutions such as the use of an air drill and miniplates have facilitated the procedure, it has gained more widespread use as a posterior approach for intraspinal surgery. Thus, with a sufficient number of patients treated and a longer period of follow up, it seems reasonable to critically evaluate the technique and its suitability as a standard approach for intraspinal surgery.

METHODS

The surgical procedures of 79 patient who underwent intraspinal surgery with osteotomy and reconstruction of a total of 323 spinal laminae using an air drill and miniplates were analyzed. In 59 patients, data of a complete clinical and radiologic follow-up examination were evaluated. Plain radiographs and computed tomography scans were analyzed for bony healing of the laminae and spinal alignment.

RESULTS

Minor complications such as cerebrospinal fluid collections and disturbed wound healing occurred within normal ranges. The was no case of dural, nerve root, or spinal cord injury attributable to laminotomy or laminar reconstruction. Eight (14.3%) patients complained of moderate to severe local pain at the time of follow-up examination and 8 patients stated impaired mobility of their spine at the surgical site. Bony healing was confirmed radiologically in 86.1% of the laminae. In 12 patients, a preexisting spinal deformity worsened after surgery and five patients demonstrated a new spinal malalignment. No patient required additional surgery because of progressive spinal deformity. Intramedullary location of the lesion and cervical location of surgery were significantly associated with the development of spinal malalignment, whereas incomplete bony healing of the laminae was not.

CONCLUSIONS

The reconstruction of the laminar roof using the technique described is safe, well suitable to serve as a standard posterior approach to intraspinal pathologies, and offers distinct advantages over laminectomy. However, some patients, particularly those with intramedullary cervical lesions, could develop spinal malalignment after surgery despite reconstruction of the laminar roof and sufficient bony healing of the laminae.

Kinematic magnetic resonance imaging of a thoracic spinal extradural arachnoid cyst: an alternative suggestion for exacerbation of symptoms during straining

STUDY DESIGN

A case study of an extradural arachnoid cyst using kinematic magnetic resonance imaging.

OBJECTIVES

To access the dynamic and pathologic changes of an extradural subarachnoid cyst during straining by kinematic magnetic resonance imaging and to clarify the pathomechanism of a fluctuation in symptoms.

SUMMARY OF BACKGROUND DATA

Extradural arachnoid cysts of the spine are an uncommon cause of myelopathy secondary to spinal cord compression; however, the precise mechanism of cord compression and subsequent symptoms remain unclear.

METHODS

A 31-year-old female presented with severe left lower thoracic back pain and leg stiffness, which were exacerbated by coughing and straining. She was diagnosed with an extradural subarachnoid cyst by magnetic resonance imaging. Kinematic magnetic resonance imaging was carried out to assess the dynamic change of the extradural cyst and to demonstrate the mechanism causing her chest pain and leg stiffness during straining.

RESULTS

Kinematic magnetic resonance imaging demonstrated that the cyst wall was compressed, and the size of extradural cyst was decreased for several seconds during straining. Furthermore, the ring of cerebrospinal fluid was gradually compressed circumferentially. After surgery, the patient experienced complete relief of symptoms. Postoperative kinematic magnetic resonance imaging revealed good decompressive results had been obtained, and the ring of cerebrospinal fluid was preserved even when the patient strained for a few minutes.

CONCLUSIONS

Kinematic magnetic resonance imaging study demonstrated that pressure changes which occur in the extradural space as well as in the arachnoid cyst might cause spinal cord compression and result in intermittent exacerbation of symptoms.

Giant intrasacral cellular schwannoma treated with high sacral amputation

STUDY DESIGN

A case report of a man with a gigantic cellular schwannoma in the sacrum treated with high sacral amputation accompanied by careful nerve root-sparing dissection.

OBJECTIVES

To describe the atypical clinical course of an intrasacral cellular schwannoma and the surgical procedure of high sacral amputation performed in a way to prevent needless sacrifice of functionally essential nerve roots.

SUMMARY OF BACKGROUND DATA

Fundamentally, a cellular schwannoma is a benign tumor, but the clinical course is atypical. The symptoms are mild and the clinicopathologic features often mislead us to make a diagnosis of malignancy. The occurrence rate of intraosseous cellular schwannoma was reported to be 0.2% of all bony tumors, and the main location was the retroperitoneal space in the pelvis. Forty-one cases of giant intrasacral schwannomas have been reported so far. Among them, large sacral schwannoma with anterior cortex erosion and associated intrapelvic extension was extremely rare.

METHODS

The patient presented with a 5-year history of right leg and buttock pain, which did not disturb his daily activities. After a histopathologic diagnosis and a complete set of image studies, high sacral amputation with preservation of uninvolved nerve roots was performed at S1-S2 through a combined anterior and posterior approach. Both S1 nerve roots and the right S2-S3 nerve roots were saved using a threaded saw. The lumbar spine was stabilized to the pelvic girdle using spinal instrumentation with posterolateral fusion.

RESULTS

Eighteen months after the tumor was resected the patient had a very good clinical outcome, and there were no radiologic signs of instability or recurrence of the tumor. Locomotor function of both lower extremities and bowel and urinary functions were well maintained. The patient returned to his previous work.

CONCLUSIONS

High sacral amputation following a combined anteroposterior approach provided good results without causing any disability. A detailed preoperative planning and careful dissection of uninvolved nerve roots prevented unnecessary neurologic impairment in locomotion and the detrusor and anorectal function.

Sacral cyst managed with cyst-subarachnoid shunt: a technical case report

STUDY DESIGN

This report describes the cyst-subarachnoid shunt, a novel surgical treatment, for sacral cysts.

OBJECTIVE

To introduce a new surgical technique for sacral cysts.

SUMMARY OF BACKGROUND DATA

There is no consensus on the appropriate treatment for symptomatic sacral cysts. The hydrostatic and pulsatile forces of cerebrospinal fluid are attributed to the growth of the cyst and their becoming symptomatic.

METHODS

The clinical and radiologic features of a 41-year-old man with a symptomatic sacral cyst are detailed. A cyst-subarachnoid shunt was set to equalize the cerebrospinal fluid pressure between the cephalad thecal sac and the cyst.

RESULTS

Immediately after surgery, the patient had no pain in his left leg and was free of pain at 2 years. Magnetic resonance imaging 1 year after surgery showed a decrease in the size of the cyst.

CONCLUSION

Although this is a preliminary study, a cyst-subarachnoid shunt can be a useful alternative for symptomatic sacral cysts.