Jonathan N. Sellin

Factors affecting survival in 43 consecutive patients after surgery for spinal metastases from thyroid carcinoma

OBJECT Spinal metastases account for the majority of bone metastases from thyroid cancer. The objective of the current study was to analyze a series of consecutive patients undergoing spinal surgery for thyroid cancer metastases in order to identify factors that influence overall survival. METHODS The authors retrospectively reviewed the records of all patients who underwent surgery for spinal metastases from thyroid cancer between 1993 and 2010 at the University of Texas MD Anderson Cancer Center. RESULTS Forty-three patients met the study criteria. Median overall survival was 15.4 months (95% CI 2.8-27.9 months) based on the Kaplan-Meier method. The median follow-up duration for the 4 patients who were alive at the end of the study was 39.4 months (range 1.7-62.6 months). On the multivariate Cox analysis, progressive systemic disease at spine surgery and postoperative complications were associated with worse overall survival (HR 8.98 [95% CI 3.46-23.30], p < 0.001; and HR 2.86 [95% CI 1.30-6.31], p = 0.009, respectively). Additionally, preoperative neurological deficit was significantly associated with worse overall survival on the multivariate analysis (HR 3.01 [95% CI 1.34-6.79], p = 0.008). Conversely, preoperative embolization was significantly associated with improved overall survival on the multivariate analysis (HR 0.43 [95% CI 0.20-0.94], p = 0.04). Preoperative embolization and longer posterior construct length were significantly associated with fewer and greater complications, respectively, on the univariate analysis (OR 0.24 [95% CI 0.06-0.93] p = 0.04; and OR 1.24 [95% CI 1.02-1.52], p = 0.03), but not the multivariate analysis. CONCLUSIONS Progressive systemic disease, postoperative complications, and preoperative neurological deficits were significantly associated with worse overall survival, while preoperative spinal embolization was associated with improved overall survival. These factors should be taken into consideration when considering such patients for surgery. Preoperative embolization and posterior construct length significantly influenced the incidence of postoperative complications only on the univariate analysis.

Prognostic Factors Influencing the Outcome of 64 Consecutive Patients Undergoing Surgery for Metastatic Melanoma of the Spine

BACKGROUND Melanoma metastases to the spine remain a challenge for neurosurgeons. OBJECTIVE To identify factors associated with survival in a series of patients who underwent spinal surgery for metastatic melanoma. METHODS We retrospectively reviewed all patients (n = 64) who received surgical intervention for melanoma metastases to the spine at the University of Texas MD Anderson Cancer Center between July 1993 and March 2012. RESULTS No patients were excluded from the study, and vital status data were available for all patients. Median overall survival was 5.7 months (95% confidence interval, 2.7-28.7). On univariate survival analysis, diagnosis of spinal metastasis after prior diagnosis of systemic metastasis, higher total spinal disease burden (including but not exclusive to the operative site), presence of progressive systemic disease at the moment of spine surgery, and postoperative complications were associated with poorer overall survival, whereas the presence of only bone metastasis at the moment of surgery was associated with improved overall survival. On multivariate survival analysis, both progressive systemic disease at the moment of spine surgery and total spinal disease burden of ≥3 vertebral levels were significantly associated with worse overall survival (hazard ratio, 6.00; 95% confidence interval, 3.19-11.28; P < .001; and hazard ratio, 2.87; 95% confidence interval, 1.62-5.07; P < .001, respectively). CONCLUSION On multivariate analysis, involvement of ≥3 vertebral bodies and progressive systemic disease were associated with worse overall survival. Consideration of these factors should influence surgical decision making in this patient population.

Spontaneous resolution of spinal epidural lipomatosis

Spinal epidural lipomatosis (SEL) is an abnormal accumulation of unencapsulated, epidural fat. SEL can be divided into idiopathic and secondary. Secondary SEL is often associated with chronic steroid use and endocrinopathies. Idiopathic SEL has been associated with obesity. SEL has been implicated in a variety of neurologic impairments and surgical decompression has been shown to prevent further worsening or result in improvement. We report a 53-year-old man with obesity and a history of chronic back pain who developed idiopathic SEL diagnosed by MRI, which subsequently resolved completely over an 8 month follow-up period. To our knowledge, this is the first reported case of complete radiographic resolution of SEL without any treatment.

Safety of epidural triamcinolone acetonide use during lumbar decompression surgery in pediatric patients: an association with delayed pseudomeningocele formation

OBJECTIVE The complication profile of epidural triamcinolone acetonide use during lumbar decompression surgery is not known. However, isolated reports of increased risk of delayed CSF leakage with the use of triamcinolone acetonide in adult spinal surgery patients have been published. The purpose of this study was to determine the safety of epidural triamcinolone acetonide use in conjunction with lumbar decompression surgery in pediatric patients. METHODS The medical records of all patients who underwent lumbar decompression surgery with or without discectomy between July 1, 2007, and July 31, 2015, were retrospectively reviewed. RESULTS During the study period, 58 patients underwent 59 spine procedures at Texas Childrens Hospital. There were 33 female and 25 male patients. The mean age at surgery was 16.5 years (range 12-24 years). Patients were followed for an average of 38.2 months (range 4-97 months). Triamcinolone acetonide was used in 28 (of 35 total) cases of discectomy; there were no cases of delayed symptomatic CSF leaks (0%) in the minimally invasive and open discectomies. On the other hand, triamcinolone acetonide was used in 14 (of 24 total) cases of multilevel laminectomy, among which there were 10 delayed CSF leaks (71.4%) requiring treatment. The use of triamcinolone acetonide in patients who underwent multilevel laminectomy was significantly associated with an increased risk of delayed CSF leaks or pseudomeningoceles (Fishers exact test, p < 0.001). CONCLUSIONS There was an unacceptable incidence of delayed postoperative CSF leaks when epidural triamcinolone acetonide was used in patients who underwent multilevel laminectomy.

Microvascular decompression of a C-2 segmental-type vertebral artery producing trigeminal hypesthesia

The authors report a case of trigeminal hypesthesia caused by compression of the spinal cord by a C-2 segmental-type vertebral artery (VA) that was successfully treated with microvascular decompression. Aberrant intradural VA loops have been reported as causes of cervical myelopathy, some of which improved with microvascular decompression. A 52-year-old man presented with progressive complaints of headache, dizziness, left facial numbness, and left upper-extremity paresthesia that worsened when turning his head to the right. Magnetic resonance imaging of the cervical spine showed the left VA passing intradurally between the axis and atlas, foregoing the C-1 foramen transversarium, and impinging on the spinal cord. The patient underwent left C-1 and C-2 hemilaminectomies followed by microvascular decompression of an aberrant VA loop compressing the spinal cord. The patient subsequently reported complete resolution of symptoms.

Developmental Considerations in Pediatric Skull Base Surgery

Objectives To review developmental surgical anatomy and technical nuances related to pediatric skull base surgery. Design Retrospective, single‐center case series with literature review. Setting MD Anderson Cancer Center. Participants Patients undergoing pediatric skull base surgery. Main Outcome Measures Review developmental anatomy of the pediatric skull base as it relates to technical nuance of various surgical approaches and insight gained from a 25‐year institutional experience with this unique patient population. Results Thirty‐nine patients meeting these criteria were identified over a 13‐year period from 2003 to 2016 and compared to a previously reported earlier cohort from 1992 to 2002. The most common benign pathologies included nerve sheath tumors (11%), juvenile nasopharyngeal angiofibromas (9.5%), and craniopharyngiomas (4.8%). The most common malignancies were chondrosarcoma (11%), chordoma (11%), and rabdomyosarcoma (11%). Varied surgical approaches were utilized and were similar between the two cohorts save for the increased use of endoscopic surgical techniques in the most recent cohort. The most common sites of tumor origin were the infratemporal fossa, sinonasal cavities, clivus, temporal bone, and parasellar region. Gross total resection and postoperative complication rates were similar between the two patient cohorts. Conclusions Pediatric skull base tumors, while rare, often are treated surgically, necessitating an in depth understanding of the anatomy of the developing skull base.

Transcavernous Approach to the Basilar Apex: A Cadaveric Prosection

The transcavernous approach to the basilar artery, as initially described by Dolenc, is one of the most common and elegant approaches to the region. It affords a generous working and viewing angle, but it can be technically challenging and requires attention to detail at each step. We investigate this approach in this report via a cadaveric prosection with a focus on the value of each of the component steps in improving surgical view and exposure. The transcavernous approach steps are divided into extradural stages: orbitozygomatic osteotomy (a modern adjunct to Dolenc’s original description), drilling of the lesser sphenoid wing, and anterior clinoidectomy; and intradural stages: wide splitting of the Sylvian fissure, unroofing of the oculomotor and trochlear nerves, and posterior clinoidectomy. The surgical windows afforded by each step in the approach are illustrated using microscopic images taken during the cadaveric prosection of a donor who happened to harbor a basilar apex aneurysm. An illustrative case and artist illustrations are used to emphasize the relative value of each step of the transcavernous exposure.

Feasibility and safety of using thoracic and lumbar cortical bone trajectory pedicle screws in spinal constructs in children: technical note

Thoracic and lumbar cortical bone trajectory pedicle screws have been described in adult spine surgery. They have likewise been described in pediatric CT-based morphometric studies; however, clinical experience in the pediatric age group is limited. The authors here describe the use of cortical bone trajectory pedicle screws in posterior instrumented spinal fusions from the upper thoracic to the lumbar spine in 12 children. This dedicated study represents the initial use of cortical screws in pediatric spine surgery. The authors retrospectively reviewed the demographics and procedural data of patients who had undergone posterior instrumented fusion using thoracic, lumbar, and sacral cortical screws in children for the following indications: spondylolysis and/or spondylolisthesis (5 patients), unstable thoracolumbar spine trauma (3 patients), scoliosis (2 patients), and tumor (2 patients). Twelve pediatric patients, ranging in age from 11 to 18 years (mean 15.4 years), underwent posterior instrumented fusion. Seventy-six cortical bone trajectory pedicle screws were placed. There were 33 thoracic screws and 43 lumbar screws. Patients underwent surgery between April 29, 2015, and February 1, 2016. Seven (70%) of 10 patients with available imaging achieved a solid fusion, as assessed by CT. Mean follow-up time was 16.8 months (range 13-22 months). There were no intraoperative complications directly related to the cortical bone trajectory screws. One patient required hardware revision for caudal instrumentation failure and screw-head fracture at 3 months after surgery. Mean surgical time was 277 minutes (range 120-542 minutes). Nine of the 12 patients received either a 12- or 24-mg dose of recombinant human bone morphogenic protein 2. Average estimated blood loss was 283 ml (range 25-1100 ml). In our preliminary experience, the cortical bone trajectory pedicle screw technique seems to be a reasonable alternative to the traditional trajectory pedicle screw placement in children. Cortical screws seem to offer satisfactory clinical and radiographic outcomes, with a low complication profile.