Inadequate Spinal Anesthesia in Lumbar Spine Surgery Is Related to Volume of the Thecal Sac.

BACKGROUND: Spinal anesthesia (SA) is used in lumbar surgery, but initial adequate analgesia fails in some patients. In these cases, spinal redosing or conversion to general endotracheal anesthesia is required, both of which are detrimental to the patient experience and surgical workflow. METHODS: We reviewed cases of lumbar surgery performed under SA from 2017-2021. We identified 12 cases of inadequate first dose and then selected 36 random patients as controls. We used a measurement tool to approximate the volume of the dural sac for each patient using T2-weighted sagittal magnetic resonance imaging sequences. RESULTS: Patients who had an inadequate first dose of anesthesia had a significantly larger dural sac volume, 22.8 ± 7.9 cm3 in the inadequate dose group and 17.4 ± 4.7 cm3 in controls (P = 0.043). The inadequate dose group was significantly younger, 54.2 ± 8.8 years in failed first dose and 66.4 ± 11.9 years in controls (P = 0.001). The groups did not differ by surgical procedure (P = 0.238), level (P = 0.353), American Society of Anesthesia score (P = 0.546), or comorbidities. CONCLUSIONS: We found that age, larger height, and dural sac volume are risk factors for an inadequate first dose of SA. The availability of spinal magnetic resonance imaging in patients undergoing spine surgery allows the preoperative measurement of their thecal sac size. In the future, these data may be used to personalize spinal anesthesia dosing on the basis of individual anatomic variables and potentially reduce the incidence of failed spinal anesthesia in spine surgery.

Spinal anesthesia in elective lumbar spinal surgery.

Spinal anesthesia (SA) is gaining recognition as a safe and efficacious regional alternative to general anesthesia for elective lumbar surgery. However, unfamiliarity with management issues related to its use has limited the adoption of awake spine surgery, despite its benefits. Few centers in the United States routinely offer SA for elective lumbar surgery, and a comprehensive workflow to standardize SA for lumbar surgery is lacking. In this article, we examine recent literature on the use of SA in lumbar surgery, review the experience of our institution with SA in lumbar surgery, and provide a cohesive outline to streamline the implementation of SA from the perspective of the anesthesiologist. We review the critical features of SA in contemporary lumbar surgery, including selection of patients, methods of SA, intraoperative sedation, and management of several important technical considerations. We aimed to flatten the learning curve to improve the availability and accessibility of the technique for eligible patients.

Intraoperative Triggered Electromyography for Pedicle Screw Placement Under Spinal Anesthesia: A Preliminary Report.

BACKGROUND: Triggered electromyography (tEMG) is an intraoperative neuromonitoring technique used to assess pedicle screw placement during instrumented fusion procedures. Although spinal anesthesia is a safe alternative to general anesthesia in patients undergoing lumbar fusion, its use may potentially block conduction of triggered action potentials or may require higher threshold currents to elicit myotomal responses when using tEMG. Given the broad utilization of tEMG for confirmation of pedicle screw placement, adoption of spinal anesthesia may be hindered by limited studies of its use alongside tEMG. OBJECTIVE: To investigate whether spinal anesthesia affects the efficacy of tEMG, we compare the baseline spinal nerve thresholds during lumbar fusion procedures under general vs spinal anesthesia. METHODS: Twenty-three consecutive patients (12 general and 11 spinal) undergoing single-level transforaminal lumbar interbody fusion were included in the study. Baseline nerve threshold was determined through direct stimulation of the spinal nerve using tEMG. RESULTS: Baseline spinal nerve threshold did not differ between the general and spinal anesthesia cohorts (3.25 ± 1.14 vs 3.64 ± 2.16 mA, respectively; P = .949). General and spinal anesthesia cohorts did not differ by age, body mass index, American Society of Anesthesiologists score status, or surgical indication. CONCLUSION: We report that tEMG for pedicle screw placement can be safely and effectively used in procedures under spinal anesthesia. The baseline nerve threshold required to illicit a myotomal response did not differ between patients under general or spinal anesthesia. This preliminary finding suggests that spinal anesthetic blockade does not contraindicate the use of tEMG for neuromonitoring during pedicle screw placement.

Clinical Outcomes of Liposomal Bupivacaine Erector Spinae Block in Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery.

BACKGROUND: Postoperative pain is a barrier to early mobility and discharge after lumbar surgery. Liposomal bupivacaine (LB) has been shown to decrease postoperative pain and narcotic consumption after transforaminal lumbar interbody fusions (TLIFs) when injected into the marginal suprafascial/subfascial plane-liposomal bupivacaine (MSSP-LB). Erector spinae plane (ESP) infiltration is a relatively new analgesic technique that may offer additional benefits when performed in addition to MSSP-LB. OBJECTIVE: To evaluate postoperative outcomes of combining ESP-LB with MSSP-LB compared with MSSP-LB alone after single-level TLIF. METHODS: A retrospective analysis was performed for patients undergoing single-level TLIFs under spinal anesthesia, 25 receiving combined ESP-LB and MSSP-LB and 25 receiving MSSP-LB alone. The primary outcome was length of hospitalization. Secondary outcomes included postoperative pain score, time to ambulation, and narcotics usage. RESULTS: Baseline demographics and length of surgery were similar between groups. Hospitalization was significantly decreased in the ESP-LB + MSSP-LB cohort (2.56 days vs 3.36 days, P = .007), as were days to ambulation (0.96 days vs 1.29 days, P = .026). Postoperative pain area under the curve was significantly decreased for ESP-LB + MSSP-LB at 12 to 24 hours (39.37 ± 21.02 vs 53.38 ± 22.11, P = .03) and total (44.46 ± 19.89 vs 50.51 ± 22.15, P = .025). Postoperative narcotic use was significantly less in the ESP-LB + MSSP-LB group at 12 to 24 hours (13.18 ± 4.65 vs 14.78 ± 4.44, P = .03) and for total hospitalization (137.3 ± 96.3 vs 194.7 ± 110.2, P = .04). CONCLUSION: Combining ESP-LB with MSSP-LB is superior to MSSP-LB alone for single-level TLIFs in decreasing length of hospital stay, time to ambulation, postoperative pain, and narcotic use.

Radiographic risk factors for intracranial hemorrhage in patients with left ventricular assist devices.

OBJECTIVE: Intracranial hemorrhage (ICH) in patients with left ventricular assist devices (LVAD) is a devastating complication. Demographic risk factors for ICH in LVAD patients are defined, however anatomic predispositions to ICH are unknown. We sought to interrogate intracranial radiographic risk factors for ICH in LVAD patients. METHODS: We reviewed 440 patients who received an LVAD from 2008-2021. We selected patients with CT scans of the head either before or after LVAD placement, but typically within 5 years. 288 patients (21 ICH, 267 Control) with imaging were included. A detailed chart review was performed on demographics, radiographic features, and management. RESULTS: The incidence of ICH in our total cohort was 8.6% (38/440). The presence of pump thrombosis (p=0.001), driveline infection (p=0.034), other hemorrhage (p=0.001), or previous placement of a cardio-defibrillator (p=.003) was associated with increased risk for ICH. An analysis of imaging revealed that the presence of a mass (p=0.006), vascular pathology (p=0.001), and microangiopathy (p=0.04) was significantly associated with ICH in LVAD patients. These radiographic features were validated with a multivariate logistic regression which confirmed presence of a mass (aOR 332.1, 95% CI: 14.7-7485.1, p<0.001), vascular pathology (aOR 69.7, 95% CI: 1.8-2658.8, p=0.022), and microangiopathy (aOR 6.5, 95% CI: 1.1-37.6, p=0.035) were independently associated with ICH. CONCLUSION: Radiographic evidence of microangiopathy, intracranial mass, and vascular pathology are independent risk factors for ICH which are readily identified by imaging. We advocate that CT imaging be used to further stratify patients at highest risk of ICH during treatment with an LVAD.

The use of intra-operative navigation during complex lumbar spine surgery under spinal anesthesia.

BACKGROUND: Spinal anesthesia is a safe and effective alternative to general anesthesia in both simple and complex lumbar surgery with numerous reported advantages leading to increased recent utilization. One potential barrier to the use of spinal anesthesia in lumbar surgery is the popularity of intraoperative computed tomography (CT) imaging. Intraoperative CT necessitates motionless patients and adds time to procedures, issues that may make surgeons hesitant to use concomitant spinal anesthesia. To date, the use of both techniques simultaneously has not been well described. OBJECTIVE: We propose that single-level lumbar fusions utilizing intraoperative CT scan acquisition and navigated instrumentation are feasible under single-dose spinal anesthesia without detrimental effect on image quality and navigation accuracy or need for spinal anesthetic re-dosing due to the additional time necessary. METHODS: We describe operative characteristics and intra-operative timing for our first five cases of transforaminal lumbar interbody fusion (TLIF) completed with intraoperative CT scan acquisition and navigated instrumentation performed under spinal anesthesia. RESULTS: The five patients ranged in age from 59 to 79 years, with an average body mass index of 27.0 kg/m2. The average total operative time for each surgery 109.2 min, including approximately 6.3 min required for CT scan acquisition. There were no complications and post-operative imaging demonstrated no malpositioned pedicle screws. CONCLUSION: Single-level TLIF procedures utilizing intraoperative CT acquisition and navigated instrumentation can be feasibly completed under single-dose spinal anesthesia without need for intraoperative apneic periods and without deleterious effect on instrumentation accuracy.

Post-operative quadriparesis following posterior cervical laminectomy and fusion: A case-series of incidence, risk factors, and management.

OBJECTIVE: Post-operative quadriparesis following posterior cervical decompression and fusion is a rare but devastating complication. Unless rapidly identified and treated, it can cause permanent injury and disability. Given the sparse literature on this topic we intend to report on its incidence, to identify potential predisposing risk factors, and to discuss management considerations. METHODS: We retrospectively reviewed a series of 301 patients who underwent posterior cervical decompressive laminectomies and instrumented fusion performed by the senior author between 2006 and 2020. We describe the clinical courses and interventions for the seven of these 301 patients who developed post-operative quadriparesis. RESULTS: The incidence of post-operative quadriparesis following cervical spine decompressive laminectomies and instrumented fusion was 2.3% (7/301) in our study. The mean time-to-onset was 2 days, and the most common pathology was post-operative hematoma. We did not identify any statistically significant risk factors that predispose patients to post-operative quadriparesis. In our series, the patients with post-operative quadriparesis without profound hypotension who underwent emergent surgical decompression demonstrated improved neurologic outcomes compared to those who underwent interval imaging prior to decompression. CONCLUSION: Post-operative quadriparesis following cervical spine surgery is a catastrophic complication that is poorly reported and under-studied in current literature. In this study, we found a 2.3% incidence of post-operative quadriparesis with no obvious risk factors predisposing patients to this adverse outcome. We advocate that post-operative quadriparesis following cervical spine surgery, in the absence of profound hypotension, warrants emergent surgical site exploration without delay for interval imaging.

Spinal anesthesia in contemporary and complex lumbar spine surgery: experience with 343 cases.

OBJECTIVE: Spinal anesthesia (SA) is an alternative to general anesthesia (GA) for lumbar spine surgery, including complex instrumented fusion, although there are relatively few outcome data available. The authors discuss their experience using SA in a modern complex lumbar spine surgery practice to describe its utility and implementation. METHODS: Data from patients receiving SA for lumbar spine surgery by one surgeon from March 2017 to December 2020 were collected via a retrospective chart review. Cases were divided into nonfusion and fusion procedure categories and analyzed for demographics and baseline medical status; pre-, intra-, and postoperative events; hospital course, including Acute Pain Service (APS) consults; and follow-up visit outcome data. RESULTS: A total of 345 consecutive lumbar spine procedures were found, with 343 records complete for analysis, including 181 fusion and 162 nonfusion procedures and spinal levels from T11 through S1. The fusion group was significantly older (mean age 65.9 ± 12.4 vs 59.5 ± 15.4 years, p < 0.001) and had a significantly higher proportion of patients with American Society of Anesthesiologists (ASA) Physical Status Classification class III (p = 0.009) than the nonfusion group. There were no intraoperative conversions to GA, with infrequent need for a second dose of SA preoperatively (2.9%, 10/343) and rare preoperative conversion to GA (0.6%, 2/343) across fusion and nonfusion groups. Rates of complications during hospitalization were comparable to those seen in the literature. The APS was consulted for 2.9% (10/343) of procedures. An algorithm for the integration of SA into a lumbar spine surgery practice, from surgical and anesthetic perspectives, is also offered. CONCLUSIONS: SA is a viable, safe, and effective option for lumbar spine surgery across a wide range of age and health statuses, particularly in older patients and those who want to avoid GA. The authors' protocol, based in part on the largest set of data currently available describing complex instrumented fusion surgeries of the lumbar spine completed under SA, presents guidance and best practices to integrate SA into contemporary lumbar spine practices.

C1-2 cyst presenting with syringobulbia: a case report.

Extradural atlantoaxial cysts are typically related to C1-2 degeneration. Intradural cysts may cause secondary syringobulbia depending on the size and cerebrospinal fluid flow obstruction. However, medullary syrinxes have not been previously described with extradural cysts. Treatment of symptomatic lesions involves surgical resection, often via a far-lateral approach, with consideration of fusion if C1-2 instability is present. We present a case of an extradural C1-2 cyst with intradural extension causing syringobulbia. Effective surgical resection was accomplished via a far-lateral, partial transcondylar approach without fusion. It is important to recognize that cysts of extradural origin may exhibit intradural extension and compress critical neurovascular structures.

Hydrodissection of Wiltse's Plane to Facilitate Exposure During Minimally Invasive Transforaminal Lumbar Interbody Fusion.

Traditional posterior lumbar approaches in a transforaminal lumbar interbody fusion (TLIF) require subperiosteal dissection of bilateral paraspinal muscles to provide adequate exposure. This may traumatize the multifidus muscle and its afferent innervations leading to postoperative paraspinal muscle atrophy. Minimizing such intraoperative trauma has been identified as an important factor in the reduction of postoperative lumbar pain. An approach via a blunt dissection through Wiltse's plane, which lies between the longissimus and multifidus muscles, may minimize postoperative pain. Definition of this plane may be facilitated by local injection of 1% lidocaine within the plane itself, as well as in the musculature defining its borders. In this paper, we demonstrate this technique with a 55-year-old female patient who presented with left-sided radicular leg pain in an L5 distribution. Wiltse plane hydrodissection was utilized in performing an L4-5 TLIF. Ultrasound images of the patient's sub-fascial musculature were obtained pre- and posthydrodissection to assess the elucidation of this plane through this technique. Intraoperative images were obtained following dissection of Wiltse's plane to further illustrate the facilitation of exposure of Wiltse's plane through hydrodissection. Postoperatively the patient did well citing a complete resolution of her radicular pain. She did not require intravenous (IV) pain medication, as her postoperative pain was well controlled with oral pain medication. She was mobilized on post-op day one, and discharged home on post-op day two with minimal back pain. Our initial experience supports the feasibility, safety, and effectiveness of hydrodissection of Wiltse's plane to facilitate exposure during a minimally invasive TLIF and thereby reducing postoperative pain.

The Role of Liposomal Bupivacaine in Reduction of Postoperative Pain After Transforaminal Lumbar Interbody Fusion: A Clinical Study.

BACKGROUND: Postoperative pain after transforaminal lumbar interbody fusion (TLIF) is a barrier to early mobility. Intraoperative local infiltration of anesthetic agents is standard practice to alleviate postoperative pain. Liposomal formulations may prolong the action of these anesthetic agents. The purpose of this study was to investigate the role of liposomal bupivacaine in postoperative pain control in patients undergoing unilateral, single-level TLIF. METHODS: From a cohort of 74 patients, half received nonliposomal local anesthetic and half received liposomal bupivacaine (LB) (LB group) via local infiltration. Both groups received a standard postoperative analgesia regimen. Demographic information, postoperative pain scores (visual analog scale), analgesic consumption, length of stay, and complications were retrospectively collected. RESULTS: The area under the curve of cumulative pain scores was significantly lower in the LB group between 0 and 12 hours (15.0 ± 15.6 vs. 45.6 ± 21.1, P = 0.003) and between 12 and 24 hours (37.6 ± 20.6 vs. 48.4 ± 24.9, P = 0.05) after surgery. Significantly fewer narcotic equivalents were consumed in the LB group between 12 and 24 hours (16.0 ± 13.4 mg vs. 24.1 ± 19.7 mg intravenous morphine equivalents, P = 0.04). Length of stay was significantly shorter in the LB group than in the control group (3.1 ± 0.9 days vs. 4.3 ± 1.3 days, P < .001). CONCLUSIONS: LB may be a useful adjunct during unilateral TLIF for decreasing pain and narcotic consumption in the first 24 hours after surgery and may also decrease overall length of stay.

Unilateral Pedicle Screw Fixation is Associated with Reduced Cost and Similar Outcomes in Selected Patients Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion for L4-5 Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective study of 24 patients who underwent either a bilateral or unilateral TLIF procedure for the treatment of degenerative spondylolisthesis. OBJECTIVE: To analyze differences in cost and outcome between patients undergoing minimally invasive transforaminal lumbar interbody fusion (mi-TLIF) with unilateral or bilateral pedicle screw fixation for L4-5 degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Lumbar fusion surgeries, including the TLIF procedure, have been shown to be an effective treatment for leg and low back pain caused by degenerative spondylolisthesis. Some studies have shown TLIF surgeries to be cost-effective, but there is still a paucity of data and no consensus. Unilateral TLIFs can provide the same benefits as bilateral TLIFs, but come with additional benefits of a less invasive surgery. METHODS: We retrospectively analyzed a consecutive series of patients with L4-5 degenerative stenosis and spondylolisthesis who either received a unilateral or bilateral mi-TLIF, paying particular attention to hospital cost and clinical outcome. Of the 33 patients eligible for analysis, we were able to obtain appropriate clinical and radiographic follow-up data on 24 patients (72.7%), 14 patients who underwent unilateral fixation, and 10 patients who underwent bilateral fixation. RESULTS: The cohorts were similar with regard to age, comorbidities, and demographics. Most patients reported good or excellent results, and there were no significant differences between the cohorts with regard to clinical outcome. There was one interbody graft extrusion in the unilateral cohort that required explantation, but no other hardware failures. Hospital cost was significantly lower in the unilateral cohort, and hardware savings accounted for only part of the difference. CONCLUSION: Unilateral pedicle screw fixation is an acceptable surgical strategy in patients with stable L4-5 degenerative spondylolisthesis undergoing mi-TLIF. In our series, unilateral fixation led to significant hospital cost savings without compromising clinical or radiographic outcomes.

A review of the combined medical and surgical management in patients with herpes simplex encephalitis.

BACKGROUND: Herpes simplex encephalitis (HSE) is a devastating and severe viral infection of the human central nervous system. This viral encephalitis is well known to cause severe cerebral edema and hemorrhagic necrosis with resultant increases in intracranial pressure (ICP). While medical management has been standardized in the treatment of this disease, the role of aggressive combined medical and surgical management including decompressive craniectomy and/or temporal lobectomy has not been fully evaluated. In addition, while barbiturate coma has been studied for treatment of status epilepticus associated with infectious encephalitis, its use for treatment of encephalitis associated intractable intracranial hypertension has not been fully reported. CASE DESCRIPTION: We report the case of a 22 year old female with severe herpetic encephalitis requiring aggressive ICP management utilizing all modalities (both medical and surgical) known to control ICP. She continues to have memory deficits but has made a good recovery with a Glasgow Outcome Scale score of 5. CONCLUSION: We provide evidence that aggressive combined medical and surgical therapy is warranted even in cases of severe HSE with transtentorial herniation, as there is evidence for the potential of good recovery. A detailed literature review of the medical and surgical management strategies in this disease is presented.

A minimal access far-lateral approach to foramen magnum lesions.

Objectives The far-lateral approach is widely used to treat pathology of the ventral foramen magnum. Numerous methods of exposure have been described, most of which utilize long skin incisions and myocutaneous flaps. Here we present our experience with gaining exposure through a small paramedian incision using a muscle-splitting technique. Design A cadaveric anatomical study was first performed to verify the feasibility of the approach. We then describe our experience with using the approach in 13 patients. A retrospective chart review was performed and data regarding pathology, imaging, and complications were collected. Results The cadaveric study confirmed that a small paramedian muscle-splitting approach allows sufficient exposure to approach many foramen magnum lesions. Our case series included 10 patients with meningioma, one brainstem glioblastoma, one posterior inferior cerebellar artery aneurysm, and one odontoid pannus. The exposure was adequate in all cases. For the meningioma patients, six had gross total resections and four had subtotal resection because of tumor adherence to neurovascular structures. Two patients experienced postoperative cardiovascular complications. There were no new neurologic deficits, cerebrospinal fluid leaks, or wound complications. Conclusions A small paramedian incision may be used to gain exposure and perform successful far-lateral approaches. The small exposure is likely to reduce the risk of local complications such as cerebrospinal fluid fistula and pseudomeningocele when compared with larger exposures.

Pigmented villonodular synovitis of the thoracic spine.

Pigmented villonodular synovitis (PVNS) is a proliferative lesion of the synovial membranes. Knees, hips, and other large weight-bearing joints are most commonly affected. PVNS rarely presents in the spine, in particular the thoracic segments. We present a patient with PVNS in the thoracic spine and describe its clinical presentation, radiographic findings, pathologic features, and treatment as well as providing the first comprehensive meta-analysis and review of the literature on this topic, to our knowledge. A total of 28 publications reporting 56 patients were found. The lumbar and cervical spine were most frequently involved (40% and 36% of patients, respectively) with infrequent involvement of the thoracic spine (24% of patients). PVNS affects a wide range of ages, but has a particular predilection for the thoracic spine in younger patients. The mean age in the thoracic group was 22.8 years and was significantly lower than the cervical and lumbar groups (42.4 and 48.6 years, respectively; p=0.0001). PVNS should be included in the differential diagnosis of osteodestructive lesions of the spine, especially because of its potential for local recurrence. The goal of treatment should be complete surgical excision. Although the pathogenesis is not clear, mechanical strain may play an important role, especially in cervical and lumbar PVNS. The association of thoracic lesions and younger age suggests that other factors, such as neoplasia, derangement of lipid metabolism, perturbations of humoral and cellular immunity, and other undefined patient factors, play a role in the development of thoracic PVNS.

Primary holocord ganglioneuroblastoma: case report.

The authors present a case of extensive primary intramedullary spinal CNS ganglioneuroblastoma (GNB) in a 23-year-old man. Central nervous system GNB is a poorly differentiated neuroepithelial tumor composed of neuroblasts and differentiated ganglion cells, and these lesions are extremely uncommon. Most previously reported primary intraaxial neuroblastic tumors were described in the brain. There has been only one other report of primary spinal cord CNS GNB published to date; the clinical course and prognosis for primary spinal cord tumors of this type are unknown. Similar tumor types demonstrate poor prognoses. This 23-year-old man presented after 9 months of progressive myelopathy. Admission MR imaging showed an intraaxial enhancing mass extending from C-3 to the conus medullaris, with a holocord appearance in several areas. Due to the tumor size, operative intervention was initially limited to biopsy sampling. Chemotherapy resulted in histological maturation, but initial tumor regression was temporary. The patient suffered progressive quadriparesis, and neuroimaging demonstrated slow enlargement of the tumor and an associated syrinx. Nineteen months after diagnosis, the tumor was excised to gross-total resection in a 2-stage operation. One year following resection, the patient had no radiographic recurrence and was functional in a wheelchair with minimal paresis in the upper extremities. This case represents the most extensive example of primary spinal intramedullary CNS GNB reported to date. Holocord tumors present a significant challenge to the neurosurgeon, and resection bears substantial risk of morbidity. In spinal cord CNS GNB, chemotherapy followed by complete resection may be the most effective means of tumor control.

Low complication rates of cranial and craniofacial approaches to midline anterior skull base lesions.

OBJECTIVE: Surgery is a cornerstone of treatment for a wide variety of neoplastic, congenital, traumatic, and inflammatory lesions involving the midline anterior skull base and may result in a significant anterior skull base defect requiring reconstruction. This study is a retrospective analysis of the reconstruction techniques and complications seen in a series of 58 consecutive patients with midline anterior skull base pathology treated with craniotomy or a craniofacial approach. The complication rates in this series are compared with other retrospective series and specific techniques that may reduce complications are then discussed. DESIGN: This is a retrospective analysis of 58 consecutive patients who had surgery for a midline anterior skull base lesion between January 1994 and July 2003. Data were collected regarding pathology, surgical approach, reconstruction technique, and complications. RESULTS: Twenty-nine patients underwent surgery for a meningioma (50%). The remainder had frontoethmoidal cancer, mucoceles/invasive nasal polyps, encephalocele, esthesioneuroblastoma, anterior falx dermoid cyst with a nasal sinus tract, or invasive pituitary adenoma. In most patients, a low and narrow two-piece biorbitofrontal craniotomy was used. When possible, the dura was repaired before entering the nasal cavity. Thirteen patients experienced a complication (22%). There was one case of postoperative cerebrospinal fluid (CSF) leak (2%), one case of meningitis (2%), two cases of bone flap infection (3%), and two cases of symptomatic pneumocephalus (3%). There were no deaths, no reoperations for CSF leak, and no patient had a new permanent neurologic deficit other than anosmia. CONCLUSIONS: Transcranial approaches for midline anterior skull base lesions can be performed safely with a low incidence of postoperative CSF leak, meningitis, bone flap infection, and symptomatic pneumocephalus. Our results, particularly with regard to CSF leakage, compare favorably with other retrospective series.

Complication avoidance in the treatment of malignant tumors of the skull base.

The treatment of malignant skull base tumors has improved with the development of skull base surgical approaches that allow en bloc resection of a lesion and increase the efficacy of adjuvant therapies. The anatomical complexity of these lesions and their surroundings has led to a relatively high complication rate. Infection and cerebrospinal fluid fistulas are the most common serious procedure-related complications. They result from the frequent necessity of working in a contaminated space such as the paranasal sinuses as well as from the creation of large dural and skull base defects. The authors have reviewed the literature regarding complications of surgery for malignant skull base lesions and present several techniques and strategies for minimizing their incidence by performing the craniofacial approach to anterior skull base lesions.