Laura A. Snyder

Intraoperative confocal microscopy in the visualization of 5-aminolevulinic acid fluorescence in low-grade gliomas.

OBJECTnGreater extent of resection (EOR) for patients with low-grade glioma (LGG) corresponds with improved clinical outcome, yet remains a central challenge to the neurosurgical oncologist. Although 5-aminolevulinic acid (5-ALA)-induced tumor fluorescence is a strategy that can improve EOR in gliomas, only glioblastomas routinely fluoresce following 5-ALA administration. Intraoperative confocal microscopy adapts conventional confocal technology to a handheld probe that provides real-time fluorescent imaging at up to 1000× magnification. The authors report a combined approach in which intraoperative confocal microscopy is used to visualize 5-ALA tumor fluorescence in LGGs during the course of microsurgical resection.nnnMETHODSnFollowing 5-ALA administration, patients with newly diagnosed LGG underwent microsurgical resection. Intraoperative confocal microscopy was conducted at the following points: 1) initial encounter with the tumor; 2) the midpoint of tumor resection; and 3) the presumed brain-tumor interface. Histopathological analysis of these sites correlated tumor infiltration with intraoperative cellular tumor fluorescence.nnnRESULTSnTen consecutive patients with WHO Grades I and II gliomas underwent microsurgical resection with 5-ALA and intraoperative confocal microscopy. Macroscopic tumor fluorescence was not evident in any patient. However, in each case, intraoperative confocal microscopy identified tumor fluorescence at a cellular level, a finding that corresponded to tumor infiltration on matched histological analyses.nnnCONCLUSIONSnIntraoperative confocal microscopy can visualize cellular 5-ALA-induced tumor fluorescence within LGGs and at the brain-tumor interface. To assess the clinical value of 5-ALA for high-grade gliomas in conjunction with neuronavigation, and for LGGs in combination with intraoperative confocal microscopy and neuronavigation, a Phase IIIa randomized placebo-controlled trial (BALANCE) is underway at the authors institution.

An extent of resection threshold for recurrent glioblastoma and its risk for neurological morbidity

OBJECTnDespite improvements in the medical and surgical management of patients with glioblastoma, tumor recurrence remains inevitable. For recurrent glioblastoma, however, the clinical value of a second resection remains uncertain. Specifically, what proportion of contrast-enhancing recurrent glioblastoma tissue must be removed to improve overall survival and what is the neurological cost of incremental resection beyond this threshold?nnnMETHODSnThe authors identified 170 consecutive patients with recurrent supratentorial glioblastomas treated at the Barrow Neurological Institute from 2001 to 2011. All patients previously had a de novo glioblastoma and following their initial resection received standard temozolomide and fractionated radiotherapy.nnnRESULTSnThe mean clinical follow-up was 22.6 months and no patient was lost to follow-up. At the time of recurrence, the median preoperative tumor volume was 26.1 cm(3). Following re-resection, median postoperative tumor volume was 3.1 cm(3), equating to an 87.4% extent of resection (EOR). The median overall survival was 19.0 months, with a median progression-free survival following re-resection of 5.2 months. Using Cox proportional hazards analysis, the variables of age, Karnofsky Performance Scale (KPS) score, and EOR were predictive of survival following repeat resection (p = 0.0001). Interestingly, a significant survival advantage was noted with as little as 80% EOR. Recursive partitioning analysis validated these findings and provided additional risk stratification at the highest levels of EOR. Overall, at 7 days after surgery, a deterioration in the NIH stroke scale score by 1 point or more was observed in 39.1% of patients with EOR ≥ 80% as compared with 16.7% for those with EOR < 80% (p = 0.0049). This disparity in neurological morbidity, however, did not endure beyond 30 days postoperatively (p = 0.1279).nnnCONCLUSIONSnFor recurrent glioblastomas, an improvement in overall survival can be attained beyond an 80% EOR. This survival benefit must be balanced against the risk of neurological morbidity, which does increase with more aggressive cytoreduction, but only in the early postoperative period. Interestingly, this putative EOR threshold closely approximates that reported for newly diagnosed glioblastomas, suggesting that for a subset of patients, the survival benefit of microsurgical resection does not diminish despite biological progression.

The impact of extent of resection on malignant transformation of pure oligodendrogliomas: Clinical article

OBJECTnRecent evidence suggests that a greater extent of resection (EOR) extends malignant progression-free survival among patients with low-grade gliomas (LGGs). These studies, however, rely on the combined analysis of oligodendrogliomas, astrocytomas, and mixed oligoastrocytomas-3 histological subtypes with distinct genetic and molecular compositions. To assess the value of EOR in a homogeneous LGG patient population and delineate its impact on LGG transformation, the authors examined its effect on newly diagnosed supratentorial oligodendrogliomas.nnnMETHODSnThe authors identified 93 newly diagnosed adult patients with WHO Grade II oligodendrogliomas treated with microsurgical resection at Barrow Neurological Institute. Clinical, laboratory, and radiographic data were collected retrospectively, including 1p/19q codeletion status and volumetric analysis based on T2-weighted MRI.nnnRESULTSnThe median preoperative and postoperative tumor volumes and EOR were 29.0 cm(3) (range 1.3-222.7 cm(3)), 5.2 cm(3) (range 0-156.1 cm(3)), and 85% (range 6%-100%), respectively. Median follow-up was 75.4 months, and there were 14 deaths (15%). Progression and malignant progression were identified in 31 (33%) and 20 (22%) cases, respectively. A greater EOR was associated with longer overall survival (p = 0.005) and progression-free survival (p = 0.004); however, a greater EOR did not prolong the interval to malignant progression, even when controlling for 1p/19q codeletion.nnnCONCLUSIONSnA greater EOR is associated with an improved survival profile for patients with WHO Grade II oligodendrogliomas. However, for this particular LGG patient population, the interval to tumor transformation is not influenced by cytoreduction. These data raise the possibility that the capacity for microsurgical resection to modulate malignant progression is mediated through biological mechanisms specific to nonoligodendroglioma LGG histologies.

Lumbar Spinal Fixation with Cortical Bone Trajectory Pedicle Screws in 79 Patients with Degenerative Disease: Perioperative Outcomes and Complications

OBJECTIVEnBiomechanical studies demonstrate that cortical bone trajectory pedicle screws (CBTPS) have greater pullout strength than traditional pedicle screws with a lateral-medial trajectory. CBTPS start on the pars and angulate in a mediolateral-caudocranial direction. To our knowledge, no large series exists evaluating the perioperative outcomes and safety of CBTPS.nnnMETHODSnWe retrospectively reviewed all patients who received lumbar CBTPS at our institution. Data were collected regarding patient demographics, use of image guidance, operative blood loss, hospital stay, and postoperative complications.nnnRESULTSnA total of 79 patients undergoing CBTPS fusion for degenerative lumbosacral disease with back pain were included in the analysis (42 female, 37 male; October 2011-January 2015). Twenty patients (25.3%) had previous lumbar spine surgery, 39 (49.4%) had a smoking history, and mean body mass index was 28.7. Mean length of stay was 3.5 days, and mean operative blood loss was 306.3 mL. Image guidance was used in 69 (87.3%) cases. A total of 66 (83.5%) fusions were single level, and 54 (68.4%) fusions were single level without previous surgery. There were 9 complications in 7 (8.9%) patients; these included hardware failure, pseudarthrosis, deep vein thrombosis, pulmonary embolism, epidural hematoma, and wound infection. No complications were caused by misplaced screws. Mean follow-up was 13.2 months.nnnCONCLUSIONSnAs CBTPS becomes increasingly popular among spine surgeons performing lumbar fusion, this report provides an important evaluation of technique safety and acceptable perioperative outcomes.

Spondylolysis outcomes in adolescents after direct screw repair of the pars interarticularis

OBJECTnIsthmic spondylolysis can significantly decrease functional abilities, especially in adolescent athletes. Although treatment can range from observation to surgery, direct screw placement through the fractured pars, or Bucks procedure, may be a more minimally invasive procedure than the more common pedicle screw-hook construct.nnnMETHODSnReview of surgical databases identified 16 consecutive patients treated with Bucks procedure from 2004 to 2010. Twelve patients were treated at Miami Childrens Hospital and 4 at Barrow Neurological Institute. Demographics and clinical and radiographic outcomes were recorded and analyzed retrospectively.nnnRESULTSnThe 16 patients had a median age of 16 years, and 14 were 20 years or younger at the time of treatment. Symptoms included axial back pain in 100% of patients with concomitant radiculopathy in 38%. Pars defects were bilateral in 81% and unilateral in 19% for a total of 29 pars defects treated using Bucks procedure. Autograft or allograft augmented with recombinant human bone morphogenetic protein as well as postoperative bracing was used in all cases. Postoperatively, symptoms resolved completely or partially in 15 patients (94%). Of 29 pars defects, healing was observed in 26 (89.6%) prior to 1 revision surgery, and an overall fusion rate of 97% was observed at last radiological follow-up. There were no implant failures. All 8 athletes in this group had returned to play at last follow-up.nnnCONCLUSIONSnDirect screw repair of the pars interarticularis defect as described in this series may provide a more minimally invasive treatment of adolescent patients with satisfactory clinical and radiological outcomes, including return to play of adolescent athletes.

Lateral Transpsoas Lumbar Interbody Fusion Outcomes and Deformity Correction

The lateral transpsoas approach for interbody fusion is a minimally invasive technique that has been gaining increasing popularity in the management of a variety of spinal degenerative disorders. Recently, there has been increasing utilization of this technique in the management of adult deformity. The authors present a review of the current evidence of using the lateral lumbar transpsoas approach in the correction of adult degenerative scoliosis.

Minimally invasive treatment of thoracic disc herniations.

In the past, treatment of thoracic disc herniations has not been seen as a minimally invasive procedure. This article evaluates the progression of minimally invasive techniques for the treatment of thoracic disc herniations. Discussion of the advantages and disadvantages of the approaches is noted so that surgeons may consider them while incorporating these techniques in their practice.

The Technological Development of Minimally Invasive Spine Surgery

Minimally invasive spine surgery has its roots in the mid-twentieth century with a few surgeons and a few techniques, but it has now developed into a large field of progressive spinal surgery. A wide range of techniques are now called “minimally invasive,” and case reports are submitted constantly with new “minimally invasive” approaches to spinal pathology. As minimally invasive spine surgery has become more mainstream over the past ten years, in this paper we discuss its history and development.

Techniques and outcomes of microsurgical management of ruptured and unruptured fusiform cerebral aneurysms

OBJECTIVE Fusiform cerebral aneurysms represent a small portion of intracranial aneurysms; differ in natural history, anatomy, and pathology; and can be difficult to treat compared with saccular aneurysms. The purpose of this study was to examine the techniques of treatment of ruptured and unruptured fusiform intracranial aneurysms and patient outcomes. METHODS In 45 patients with fusiform aneurysms, the authors retrospectively reviewed the presentation, location, and shape of the aneurysm; the microsurgical technique; the outcome at discharge and last follow-up; and the change in the aneurysm at last angiographic follow-up. RESULTS Overall, 48 fusiform aneurysms were treated in 45 patients (18 male, 27 female) with a mean age of 49 years (median 51 years; range 6 months-76 years). Twelve patients (27%) had ruptured aneurysms and 33 (73%) had unruptured aneurysms. The mean aneurysm size was 8.9 mm (range 6-28 mm). The aneurysms were treated by clip reconstruction (n = 22 [46%]), clip-wrapping (n = 18 [38%]), and vascular bypass (n = 8 [17%]). The mean (SD) hospital stay was 19.0 ± 7.4 days for the 12 patients with subarachnoid hemorrhage and 7.0 ± 5.6 days for the 33 patients with unruptured aneurysms. The mean follow-up was 38.7 ± 29.5 months (median 36 months; range 6-96 months). The mean Glasgow Outcome Scale score for the 12 patients with subarachnoid hemorrhage was 3.9; for the 33 patients with unruptured aneurysms, it was 4.8. No rehemorrhages occurred during follow-up. The overall annual risk of recurrence was 2% and that of rehemorrhage was 0%. CONCLUSIONS Fusiform and dolichoectatic aneurysms involving the entire vessel wall must be investigated individually. Although some of these aneurysms may be amenable to primary clipping and clip reconstruction, these complex lesions often require alternative microsurgical and endovascular treatment. These techniques can be performed with acceptable morbidity and mortality rates and with low rates of early rebleeding and recurrence.

The Influence of Common Medical Conditions on the Outcome of Anterior Lumbar Interbody Fusion.

Study Design:The authors retrospectively reviewed a consecutive series of 231 patients with anterior lumbar interbody fusion (ALIF). Objective:To determine the correlations among common medical conditions, demographics, and the natural history of lumbar surgery with outcomes of ALIF. Summary of Background Data:Multiple spinal disorders are treated with ALIF with excellent success rates. Nonetheless, adverse outcomes and complications related to patients’ overall demographics, comorbidities, or cigarette smoking have been reported. Methods:The age, sex, body mass index (BMI), comorbidities, history of smoking or previous lumbar surgery, operative parameters, and complications of 231 patients who underwent ALIF were analyzed. Regression analyses of all variables with complications and surgical outcomes based on total Prolo scores were performed. Two models predicting Prolo outcome score were generated. The first model used BMI and sex interaction, whereas the second model used sex, level of surgery, presence of diabetes mellitus, and BMI as variables. Results:At follow-up, the rate of successful fusion was 99%. The overall complication rate was 13.8%, 1.8% of which occurred intraoperatively and 12% during follow-up. The incidence of complications failed to correlate with demographics, comorbidities, smoking, or previous lumbar surgery (P>0.5). ALIF at T12–L4 was the only factor significantly associated with poor patient outcomes (P=0.024). Both models successfully predicted outcome (P=0.05), although the second model did so only for males. Conclusions:Surgical level of ALIF correlated with poor patient outcomes as measured by Prolo functional scale. BMI emerged as a significant predictor of Prolo total score. Both multivariate models also successfully predicted outcomes. Surgical or follow-up complications were not associated with patients’ preoperative status.