Neurosurgery Blog

Neurosurgery 72:300–309, 2013

Spinal metastases of the second cervical vertebra are a subset of tumors that are particularly difficult to address surgically. Previously described techniques require highly morbid circumferential dissection posterior to the pharynx for resection and reconstruction.

OBJECTIVE: To perform a biomechanical analysis of instrumented reconstruction configurations used after axial spondylectomy and to demonstrate safe use of a novel construct in a patient case report.

METHODS: Several different published and novel reconstruction configurations were inserted into 7 occipitocervical spines that underwent axial spondylectomy. A biomechanical analysis of the stiffness of the constructs in flexion and extension, lateral bending, and rotation was performed. A patient then underwent a posterior-only approach for axial spondylectomy and circumferential reconstruction.

RESULTS: Biomechanical analysis of different constructs demonstrated that anterior column reconstruction with bilateral cages spanning the C1 lateral mass to the C3 facet in combination with occipitocervical instrumentation was superior in flexion-extension and equivalent in lateral bending and rotation to currently used constructs. The patient in whom this construct was placed via a posterior-only approach for axial spondylectomy and instrumentation remained at neurological baseline and demonstrated no recurrence of local disease or failure of instrumentation to date.

CONCLUSION: When C1 lateral mass to C3 facet bilateral cage plus occipitocervical instrumentation is compared with existing anterior and posterior constructs, this novel reconstruction is biomechanically equivalent if not superior in performance. In a patient, the posterior-only approach for C2 spondylectomy with the novel reconstruction was safe and durable and avoided the morbidity of the anterior approach.

Neurosurgery 72:151–159, 2013

Surgery for scoliosis requires extensive exposure, resulting in significant tissue injury and longer recovery times. To minimize morbidity in scoliosis surgery, several studies have shown successful application of a combination of minimally invasive techniques; however, the extent of scoliosis treated has been modest.

OBJECTIVE: To achieve some of the benefits of minimally invasive surgery and yet treat curves of greater degree, we have used a combined approach, incorporating both open and minimally invasive techniques.

METHODS: We analyzed a prospectively acquired database in addition to reviewing electronic records of patients undergoing hybrid surgery for thoracolumbar scoliosis. Nine patients were identified. The minimally invasive portion involved the lumbar region in all cases. Pain was assessed by the visual analog scale and disability was measured by the Oswestry Disability Index.

RESULTS: Mean preoperative scoliosis was 47.8 degrees, which was corrected to a mean 15.2 degrees. An average of 7.8 spinal levels was treated. Estimated blood loss averaged 1094.4 mL, and length of hospital stay averaged 7.2 days. Acute complications occurred in 2 patients. Longer term complications occurred in 2 patients, consisting of adjacent segment disease. The mean improvement in the visual analog scale score was 3.7 and the mean improvement on the Oswestry Disability Index was 30.5. Average follow-up was 29.2 months.

CONCLUSION: The hybrid approach for the treatment of scoliosis results in acceptable radiographic and clinical outcomes. Complications did not appear increased compared with those expected with scoliosis surgery. Although decreased adjacent tissue injury was achieved with the minimally invasive component of the procedure, a larger comparative study is required to determine magnitude of this benefit.

J Neurosurg Spine 17:30–36, 2012

Incidental durotomies (IDs) are an unfortunate but anticipated potential complication of spinal surgery. The authors surveyed the frequency of IDs for a single spine surgeon and analyzed the major risk factors as well as the impact on long-term patient outcomes.

Methods. The authors conducted a prospective review of elective spinal surgeries performed over a 15-year period. Any surgery involving peripheral nerve only, intradural procedures, or dural tears due to trauma were excluded from analysis. The incidence of ID was categorized by surgery type including primary surgery, revision surgery, and so forth. Incidence of ID was also examined in the context of years of physician experience and training. Furthermore, the incidence and types of sequelae were examined in patients with an ID.

Results. Among 3000 elective spinal surgery cases, 3.5% (104) had an ID. The incidence of ID during minimally invasive procedures (3.3%) was similar, but no patients experienced long-term sequelae. The incidence of ID during revision surgery (6.5%) was higher. There was a marked difference in incidence between cervical (1.3%) and thoracolumbar (5.1%) cases. The incidence was lower for cases involving instrumentation (2.4%). When physician training was examined, residents were responsible for 49% of all IDs, whereas fellows were responsible for 26% and the attending for 25%. Among all of the cases that involved an ID, 7.7% of patients went on to experience a neurological deficit as compared with 1.5% of those without an ID. The overall failure rate of dural repair was 6.9%, and failure was almost 3 times higher (13%) in revision surgery as compared with a primary procedure (5%).

Conclusions. The authors established a reliable baseline incidence for durotomy after spine surgery: 3.5%. They also identified risk factors that can increase the likelihood of a durotomy, including location of the spinal procedure, type of procedure performed, and the implementation of a new procedure. The years of physician training or resident experience did not appear to be a major risk for ID.

Neurosurgery 71:117–125, 2012 DOI: 10.1227/NEU.0b013e3182532e71

The management of spinal column tumors continues to be a challenge for clinicians. The mechanisms of tumor recurrence after surgical intervention as well as resistance to radiation and chemotherapy continue to be elucidated. Furthermore, the pathophysiology of metastatic spread remains an area of active investigation.

There is a growing body of evidence pointing to the existence of a subset of tumor cells with high tumorigenic potential in many spine cancers that exhibit characteristics similar to those of stem cells. The ability to self-renew and differentiate into multiple lineages is the hallmark of stem cells, and tumor cells that exhibit these characteristics have been described as cancer stem cells (CSCs).

The mechanisms that allow nonmalignant stem cells to promote normal developmental programming by way of enhanced proliferation, promotion of angiogenesis, and increased motility may be used by CSCs to fuel carcinogenesis.

The purpose of this review is to discuss what is known about the role of CSCs in tumors of the osseous spine. First, this article reviews the fundamental concepts critical to understanding the role of CSCs with respect to chemoresistance, radioresistance, and metastatic disease. This discussion is followed by a review of what is known about the role of CSCs in the most common primary tumors of the osseous spine.

J Neurosurg: Spine / July 17, 2012. DOI: 10.3171/2012.6.SPINE11915

Axial lumbar interbody fusion (AxiaLIF) is a minimally invasive presacral surgical technique that damages neither the anulus fibrosus nor the anterior or posterior longitudinal ligaments. The technique was initially designed and used for L5–S1 interbody fusions and recently was extended to 2-level fusions (L4–5 and L5–S1). Until now, only biomechanical and radiological studies have discussed the feasibility of this new indication, and no clinical study has been published. The purpose of this article is to report results and complications associated with 2-level presacral AxiaLIF with a minimum of 24 months of follow-up.

METHODS
In this prospective, nonrandomized, single-center study, 27 patients underwent presacral AxiaLIF surgery at the L4–5 and L5–S1 levels. Clinical outcomes were assessed using the visual analog scale for back and leg symptoms and the Oswestry Disability Index. Radiographic parameters, such as disc height, segmental lordosis, and bone fusion, were analyzed using radiographs and CT scans. Complications and revision surgeries were recorded as needed. The minimum follow-up was 24 months (up to 72 months).

RESULTS
There were no intraoperative complications. One major complication was observed: a patient developed septicemia that resolved after proper care. Clinical outcomes scores showed overall improvement in pain and physical function. During follow-up, the following complications were observed in the construct: screw breakage (14.8%), proximal/distal transsacral rod detachment (11.1%), radiolucency around the transsacral rod (52%), and cephalic rod migration (24%). Disc height gain was reported early after surgery, but at the 24-month follow-up the disc space was diminished in comparison with the preoperative status. Compared with preoperative values, the 24-month results showed loss of segmental lordosis. Only 22% of all treated levels were considered to have solid fusion at the 24-month radiological evaluation.

CONCLUSIONS
Patients undergoing presacral 2-level AxiaLIF experienced satisfactory short-term clinical outcomes; however, complications were commonly seen on imaging studies obtained 24 months postoperatively. Additional studies are required to better understand the 2-level indications for this technique.

Acta Neurochir (2012) 154:871–877. DOI 10.1007/s00701-012-1313-5

Intradural spinal metastases are rare, and little is known regarding surgical indications and outcomes.

Methods A retrospective search identified adults with intradural spinal metastases operated on at the Mayo Clinic from 1994-2011. Data were collected regarding demographics, tumor type and location, and outcomes.

Results Fifteen patients with intradural spinal metastases were investigated. The age range was 38-74 years (mean= 55 years; ±SD=11.1). Predominant tumor location and type were lumbosacral and adenocarcinoma, respectively: 3 intramedullary and 12 extramedullary. Patients were operated on to relieve or prevent progressive/intractable neurological sequelae and/or pain. Of 13 who underwent resection, gross total removal was reported in 10; simple biopsy was performed in 2. There was one surgical complication, no medical complications, and no surgical mortality. At median follow-up of 1 month postoperatively, 10 of 15 patients were stable or improved. Of 13 patients who underwent resection, 10 were stable or improved. Of two patients who underwent biopsy, neither was stable or improved at follow-up. Using the Modified McCormick Scale, 11 of 15 patients were “functional” preoperatively and 4 went from “functional” preoperatively to “non-functional” postoperatively. Three of those four died within 60 days of surgery from systemic disease progression. Median hospital stay was 8 days. Ten of 15 patients died by the end of the study period, and the median survival of 15 patients was 5 months.

Conclusions With improved outcomes in metastatic cancer, more patients are encountered in practice. An aggressive surgical approach is warranted for extramedullary lesions, whereas caution is advised for intramedullary lesions. Postoperative functional decline is more likely due to systemic disease progression rather than surgery.

Neurosurgery 69:1181–1187, 2011 DOI: 10.1227/NEU.0b013e31822a9aeb

Management approaches for adult scoliosis are primarily based on adults with idiopathic scoliosis and extrapolated to adults with degenerative scoliosis. However, the often substantially, but poorly defined, greater degenerative changes present in degenerative scoliosis impact the management of these patients.

OBJECTIVE: To assess the prevalence, severity, and impact of canal and foraminal stenosis in adults with degenerative scoliosis seeking operative treatment.

METHODS: A prospectively collected database of adult patients with deformity was reviewed for consecutive patients with degenerative scoliosis seeking surgical treatment, without prior corrective surgery. Patients completed the Oswestry Disability Index, SF-12, Scoliosis Research Society 22 questionnaire, and a pain numeric rating scale (0-10). Based on MRI or CT myelogram, the central canal and foraminae from T6 to S1 were graded for stenosis (normal or minimal/mild/moderate/severe).

RESULTS: Thirty-six patients were included (mean age, 68.9 years; range, 51-85). The mean leg pain numeric rating scale was 6.5, and the mean Oswestry Disability Index score was 53.2. At least 1 level of severe foraminal stenosis was identified in 97% of patients; 83% had maximum foraminal stenosis in the curve concavity. All but 1 patient reported significant radicular pain, including 78% with discrete and 19% with multiple radiculopathies. Of those with discrete radiculopathies, 76% had pain corresponding to areas of the most severe foraminal stenosis, and 24% had pain corresponding to areas of moderate stenosis.

CONCLUSION: Significant foraminal stenosis was prevalent in patients with degenerative scoliosis, and the distribution of leg pain corresponded to levels of moderate or severe foraminal stenosis. Failure to address symptomatic foraminal stenosis when surgically treating adult degenerative scoliosis may negatively impact clinical outcomes.

Neurosurg Rev DOI 10.1007/s10143-011-0334-5

Previous studies of chordoma have focused on either surgery, radiotherapy, or particular tumor locations. This paper reviewed the outcomes of surgery and proton radiotherapy with various tumor locations.

Between 2001 and 2008, 40 patients with chordomas of the skull base and cervical spine had surgery at our hospital. Most patients received proton therapy. Their clinical course was reviewed. Age, sex, tumor location, timing of surgery, extent of resection, and chondroid appearance were evaluated in regard to the progression-free survival (PFS) and overall survival (OS). The primary surgery (PS) group was analyzed independently. The extensive resection rate was 42.5%. Permanent neurological morbidity was seen in 3.8%. Radiotherapy was performed in 75% and the mean dose was 68.9 cobalt gray equivalents. The median followup was 56.5 months. The 5-year PFS and OS rates were 70% and 83.4%, respectively. Metastasis was seen in 12.5%. The tumor location at the cranio-cervical junction (CCJ) was associated with a lower PFS (P=0.007). In the PS group, a younger age and the CCJ location were related to a lower PFS (P=0.008 and P<0.001, respectively). The CCJ location was also related to a lower OS (P=0.043) and it was more common in young patients (P=0.002). Among the survivors, the median of the last Karnofsky Performance Scale score was 80 with 25.7% of patients experiencing an increase and 11.4% experiencing a decrease.

Multimodal surgery and proton therapy thus improved the chordoma treatment. The CCJ location and a younger age are risks for disease progression.

Eur Spine J (2011) 20:934–941. DOI 10.1007/s00586-010-1588-2

Disc prostheses have been designed to restore and maintain cervical segmental motion and reduce the accelerated degeneration of the adjacent level. There is no knowledge about the reaction of the neighboured asymptomatic segments after implantation of prostheses or fusion. The effects of these procedures to segmental movement of the uninvolved vertebrae have not been subjected to studies so far.

The objective of this study was to compare the segmental motion following cervical disc replacement versus fusion and the correlation to the clinical outcome. Another aim was to compare the segmental motion of the asymptomatic segments above the treated ones and to compare both with Roentgen stereometric analysis (RSA) including the asymptomatic segments.

20 patients with one-level cervical radiculopathy scheduled for surgery were randomized to arthroplasty (10 patients, study group) or anterior cervical discectomy and fusion (10 patients, control group). Clinical results were evaluated using Visual Analogue Scale and Neck Disability Index. RSA was performed immediately postoperative, after 6 and 12 months.

The adjacent segment showed a significantly higher segmental motion in all three-dimensional axes in comparison to the segment treated with prostheses (P< 0.05). In the fusion group the segmental motion of the adjacent segment was significantly higher in all three dimensional axes (P< 0.05) at each examination time. When the adjacent level of both groups is compared, the fusion group could show a higher segmental motion in all three-dimensional axes, but without significant difference (P> 0.05) 1 year after surgery. Regarding the clinical results, there was no significant difference in pain relief between both groups (P> 0.05).

In conclusion, the adjacent segment could show a higher segmental motion, when compared with the segment either treated with prostheses or fusion. There was no significant difference in segmental motion adjacent to prosthesis or fusion. Clinical results did also show no significant difference in pain relief between both groups.

J Neurosurg Spine 14:561–569, 2011. DOI: 10.3171/2010.12.SPINE10286

Osteoporotic vertebral compression fractures (VCFs) are a major cause of increased morbidity in older patients. This randomized controlled trial compared the efficacy of percutaneous vertebroplasty (PV) versus optimal medical therapy (OMT) in controlling pain and improving the quality of life (QOL) in patients with VCFs. Efficacy was measured as the incidence of new vertebral fractures after PV, restoration of vertebral body height (VBH), and correction of deformity.

Methods. Of 105 patients with acute osteoporotic VCFs, 82 were eligible for participation: 40 patients underwent PV and 42 received OMT. Primary outcomes were control of pain and improvement in QOL before treatment, and these were measured at 1 week and at 2, 6, 12, 24, and 36 months after the beginning of the treatment. Radiological evaluation to measure VBH and sagittal index was performed before and after treatment in both groups and after 36 months of follow-up.

Results. The authors found a statistically significant improvement in pain in the PV group compared with the OMT group at 1 week (difference -3.1, 95% CI -3.72 to -2.28; p < 0.001). The QOL improved significantly in the PV group (difference -14, 95% CI -15 to -12.82; p < 0.028). One week after PV, the average VBH restoration was 8 mm and the correction of deformity was 8°. The incidence of new fractures in the OMT group (13.3%) was higher than in the PV group (2.2%; p < 0.01).

Conclusions. The PV group had statistically significant improvements in visual analog scale and QOL scores maintained over 24 months, improved VBH maintained over 36 months, and fewer adjacent-level fractures compared with the OMT group.

Neurosurgery 68:291–301, 2011 DOI: 10.1227/NEU.0b013e3182011262

Traumatic injuries of the craniovertebral junction (CVJ) area are common and frequently the outcome of motor vehicle accidents, falls, and diving accidents.

To define and characterize CVJ traumatic injuries, some international classifications are currently in use, and they are thought and focused on junction bone fracture. However, recent data point out a major important role of the CVJ ligaments and membranes in traumatic injuries with a secondary function of the osseous structures.

Emphasizing the correct role of the ligaments and membranes is extremely important for determining appropriate medical or surgical planning for patients and also to design new CVJ injury classifications.

We reviewed every recent major publication on the ligaments and membranes of the CVJ area. We divided the information into sections concerning anatomy, embryology, biomechanics, trauma, and CVJ bone fractures.

A role of the ligaments and membranes in the traumatic injuries of the CVJ area has often been recognized; but only recently, with the increase in the knowledge of the anatomic and biomechanical junction area, supported by neuroradiological tools (magnetic resonance imaging) and a more detailed traumatic injuries assessment, has the role of the ligaments and membranes been highlighted.

Ligaments and membranes have a pivotal role in each junctional ability and are the key to orienting any medical or surgical indications in this unique area of the spine.

Neurosurg Q 2010;20:107–110

Objective: To assess the safety and efficacy of outpatient anterior cervical discectomy and fusion (ACDF) carried out on outpatients.

Methods: We retrospectively reviewed the records of 390 consecutive patients who underwent outpatient ACDF between September 2002 and September 2007 to assess the safety and efficacy of outpatient anterior cervical surgery. The mean age of the patient sample was 46; 56% were female and 44% were male. Indications for surgery consisted of cervical radiculopathy or myelopathy. Charts were reviewed to define patient demographics and medical comorbidities. Operative data, including levels treated, surgery time, time to discharge, and intraoperative complications were collected. Clinical outcomes were collected using the PhDx Clinical Outcomes Database. Need for hospital transfer from the ambulatory surgical center, emergency room visits, and subsequent hospital admission in the perioperative period were determined from patient records. Complications, patient satisfaction, and outcome were ascertained through review of notes from the first postoperative visit.

Results: There was no mortality and there were no major complications. Out of 390 patients, operation was carried out at 1 level in 223 patients, at 2 levels in 143, and at 3 levels in 24. Pain was present in 99%, motor deficit in 31%, and myelopathy in 14%. Twenty-five percent were hypertensive, 5% were diabetic, and 2% had coronary artery disease. The incidence of hospital transfer for ACDF related complications was <1%, emergency room visits <1% and subsequent hospitalization <1%. At the time of the first postoperative visit 92% of patients believed that they were improved and only 1% of patients had transiently increased radicular weakness.

Conclusion: Outpatient ACDF is safe and efficacious in selected patients.

J Neurosurg Spine 11:607–613, 2009. DOI: 10.3171/2009.4.SPINE08466

Vertebroplasty is a well-known technique used to treat pain associated with vertebral. Despite a success rate of up to 90% in different series, the procedure is often associated such as cord and root compression, epidural and subdural hematomas (SDHs), and other minor complications. In this study, the authors discuss the major complications of and their clinical implications during the postoperative course.

Methods. Vertebroplasty was performed in 12 vertebrae of 7 patients. Five patients had fractures, 1 had tumoral compression fractures, and 1 had a traumatic fracture. Two leakage, 1 had epidural leakage, 1 had subdural cement leakage, 2 had a spinal SDH, and after the procedure.

Results. Three patients had paraparesis (2 had SDHs and 1 had epidural cement leakage), 3 had root symptoms, and 1 had lower back pain. Two of the 3 patients with paraparesis recovered after evacuation of the SDH and subdural cement; however, 1 patient with paraparesis did not recover after epidural cement leakage, despite cement evacuation. Two patients with foraminal leakage and 1 with subdural cement leakage had root symptoms and recovered after evacuation and conservative treatment. The patient with the split fracture had no neurological symptoms and recovered with conservative treatment.

Conclusions. Transpedicular vertebroplasty may have major complications, such as a spinal SDH and/or cement leakage into the epidural and subdural spaces, even when performed by experienced spinal surgeons. Early diagnosis with CT and intervention may prevent worsening of these complications.