J Neurosurg Spine 16:37–43, 2012. DOI: 10.3171/2011.9.SPINE11283

Present attempts to control health care costs focus on reducing the incidence of complications and hospital-acquired conditions (HACs). One approach uses restriction or elimination of hospital payments for HACs. Present approaches assume that all HACs are created equal and that payment restrictions should be applied uniformly. Patient factors, and especially patient comorbidities, likely impact complication incidence. The relationship of patient comorbidities and complication incidence in spine surgery has not been prospectively reported.

METHODS: The authors conducted a prospective assessment of complications in spine surgery during a 6-month period; an independent auditor and a validated definition of perioperative complications were used. Initial demographics captured relevant patient comorbidities. The authors constructed a model of relative risk assessment based on the presence of a variety of comorbidities. They examined the impact of specific comorbidities and the cumulative effect of multiple comorbidities on complication incidence.

RESULTS: Two hundred forty-nine patients undergoing 259 procedures at a tertiary care facility were evaluated during the 6-month duration of the study. Eighty percent of the patients underwent fusion procedures. One hundred thirty patients (52.2%) experienced at least 1 complication, with major complications occurring in 21.4% and minor complications in 46.4% of the cohort. Major complications doubled the median duration of hospital stay, from 6 to 12 days in cervical spine patients and from 7 to 14 days in thoracolumbar spine patients. At least 1 comorbid condition was present in 86% of the patients. An increasing number of comorbidities strongly correlated with increased risk of major, minor, and any complications (p = 0.017, p < 0.0001, and p < 0.0001, respectively). Patient factors correlating with increased risk of specific complications included systemic malignancy and cardiac conditions other than hypertension.

CONCLUSIONS: Comorbidities significantly increase the risk of perioperative complications. An increasing number of comorbidities in an individual patient significantly increases the risk of a perioperative adverse event. Patient factors significantly impact the relative risk of HACs and perioperative complications.

J Neurosurg Spine 16:44–50, 2012. DOI: 10.3171/2011.9.SPINE11373

Since its original description in 1982, transforaminal lumbar interbody fusion (TLIF) has grown in popularity as a means for achieving circumferential fusion. The authors sought to define the perioperative complication rates of the TLIF procedure at a large academic medical center.

Methods. For all eligible patients from a consecutive series of 531 TLIF procedures, the institution’s complication database and the medical record were reviewed to identify complications. Medical, nonprocedure-related complications such as myocardial infarction and pulmonary embolism were excluded due to inconsistency in the recording of these complications in the database. Rates were calculated for each type of complication, and subgroup analysis was performed to investigate the effect of previous lumbar surgery, and of multilevel versus single-level interbody fusion on complication rates. Odds ratios were calculated and evaluated using chi-square analysis.

Results. Five hundred thirty-one patients underwent a TLIF procedure during the study period. Two hundred forty-four patients (46%) had undergone a previous lumbar operation. Interbody fusion was performed at 1 level in 317 patients, at 2 levels in 188 patients, at 3 levels in 24 patients, and at 4 levels in 2 patients. One hundred thirty-five patients (25.4%) had at least one procedure-related complication. The most common complications were durotomy (14.3% of patients) and infection (3.8% of patients). Symptomatic screw misplacement (2.1% of patients) and interbody cage migration (1.8% of patients) were less common complications. The overall complication rate was greater in those patients who had undergone a previous operation (OR 1.75, 95% CI 1.18–2.59; p < 0.01) and in those who had multilevel surgery (OR 1.54, 95 % CI 1.04–2.28; p = 0.03), and the incidence of durotomy was higher in patients who had a previous operation (OR 1.75, 95% CI 1.07–2.87; p = 0.03). These differences were statistically significant. Durotomy also occurred more frequently in patients who had multilevel interbody fusion (OR 1.49, 95% CI 0.92–2.43; p = 0.13). A trend toward higher infection rates in those patients who underwent multilevel interbody fusion was observed (OR 1.5, 95% CI 0.62–3.68; p = 0.49), but this was not statistically significant. Infection rates did not differ between revision and first-time surgeries.

Conclusions. Transforaminal lumbar interbody fusion has gained widespread popularity as a procedure for achieving arthrodesis in the lumbar spine. Complications occurred more often in patients undergoing revision surgery or multilevel interbody fusion. Durotomy and infection were the most common complications in this series.

Neurosurgery 69:412–420, 2011 DOI: 10.1227/NEU.0b013e318213431e

In aneurysm surgery, understanding the microanatomy around the aneurysm such as perforating arteries and cranial nerves is mandatory.

OBJECTIVE: To assess the usefulness in determining the microanatomy around the cerebral aneurysms by the use of fast imaging employing steady-state acquisition (FIESTA) images of magnetic resonance imaging preoperatively, in addition to computed tomography and digital subtraction angiography.

METHODS: Between October 2006 and June 2009, 123 patients with 140 unruptured cerebral aneurysms were treated in our institution. Eighty-two patients were assessed with FIESTA by the operators on the workstation of the magnetic resonance image before surgical clipping of the aneurysms. The small vessels and cranial nerves were confirmed intraoperatively before or after obliteration of the aneurysms.

RESULTS: Sensitivities and specificities of FIESTA imaging were 100% in detecting hypothalamic artery around anterior communicating artery aneurysms, oculomotor nerve attachment to the posterior communicating artery aneurysm domes, and anterior choroidal artery adhesion to the posterior communicating artery aneurysms. This technique was also useful for predicting adhesion between the aneurysm and adjacent main trunks or perforators. Although the specificity was 100%, sensitivity was 56% in detecting vessel adhesion around the middle cerebral aneurysms. This technique can provide limited information in large aneurysms or aneurysms located in minimal cerebrospinal fluid space. The overall outcomes of the patients included 120 excellent recoveries, 1 moderate deficit, 1 severe deficit, and 1 persistent vegetative state according to the Glasgow Outcome Scale.

CONCLUSION: By giving information on the minute anatomical structure around the aneurysm, FIESTA can contribute to thorough preoperative evaluations of cerebral aneurysms.

J Neurosurg 115:202–209, 2011. DOI: 10.3171/2011.4.JNS101924

Microvascular decompression (MVD) offers an effective and durable treatment for patients suffering from trigeminal neuralgia (TN). Because the disorder has a tendency to occur in older persons, the risks of surgical treatment in the elderly have been a topic of recent interest. To date, evidence derived from several small retrospective and a single prospective case series has suggested that age does not increase the complication rate associated with surgery. Using a large national database, the authors aimed to study the impact of age on in-hospital complications following MVD for TN.

Methods. Using the Nationwide Inpatient Sample (NIS) for the 10-year period from 1999 to 2008, the authors selected all patients who underwent MVD for TN. The primary outcome of interest was the in-hospital mortality rate. Secondary outcomes of interest were cardiac, pulmonary, thromboembolic, cerebrovascular, and wound complications as well as the duration of hospital stay, total hospital charges, and discharge location. An elderly cohort of patients was first defined as those 65 years of age and older and then redefined as those 75 years and older.

Results. A total of 3273 patients who underwent MVD for TN were identified, having a median age of 57 years. Within this sample, 31.5% were 65 years and older and 10.7% were 75 years and older. The in-hospital mortality rate was 0.68% for patients 65 years or older (p = 0.0087) and 1.16% for those 75 years or older (p = 0.0026). In patients younger than 65 years, the in-hospital mortality rate was 0.13% (3 deaths among 2241 patients). As analyzed using the chi-square test (for both 65 and 75 years as the age cutoff) and the Pearson rank correlation coefficient, the risk of cardiac, pulmonary, thromboembolic, and cerebrovascular complications was higher in older patients (that is, those 65 and older and those 75 and older), but the risks of wound complications and CNS infection were not. The risk of any in-hospital complication occurring in a patient 65 years and older was 7.36% (p < 0.0001) and 10.0% in those 75 years and older (p < 0.0001). There was no difference in the total hospital charges associated with age. The duration of the hospital stay was longer in older patients, and the likelihood of discharge home was lower in older patients.

Conclusions. Microvascular decompression for TN in the elderly population remains a reasonable surgical option. However, based on data from a large national database, authors of the present study suggest that complications do tend to gradually increase in tandem with an advanced age. While age does not act as a risk factor in isolation, it may serve as a convenient surrogate for complication rates. The authors hope that this information can be of use in guiding older patients through decisions for the surgical treatment of TN.

J Neurosurg Pediatrics 8:177–183, 2011. DOI: 10.3171/2011.5.PEDS10362

Posterior fossa decompression with duraplasty for Chiari malformation Type I (CM-I) is a common pediatric neurosurgery procedure. Published series report a complication rate ranging from 3% to 40% for this procedure. Historically, many dural substitutes have been used, including bovine grafts, human cadaveric pericardium, synthetic dura, and autologous pericranium. The authors hypothesized that a recently observed increase in complications was dependent on the graft used.

Methods. Between January 2004 and January 2008, 114 consecutive patients ≤ 18 years old underwent primary CM-I decompression using duraplasty. Records were retrospectively reviewed for short- and intermediate-term complications and operative technique, focusing on the choice of duraplasty graft with or without application of a tissue sealant.

Results. The average age of the patients was 8.6 years. The dural graft used was variable: 15 were treated with cadaveric pericardium, 12 with Durepair, and 87 with EnDura. Tisseel was used in 75 patients, DuraSeal in 12, and no tissue sealant was used in 27 patients. The overall complication rate was 21.1%. The most common complications included aseptic meningitis, symptomatic pseudomeningocele, or a CSF leak requiring reoperation. The overall complication rates were as follows: cadaveric pericardium 26.7%, Durepair 41.7%, and EnDura 17.2%; reoperation rates were 13%, 25%, and 8.1%, respectively. Prior to adopting a different graft product, the overall complication rate was 18.1%; following the change the rate increased to 35%. Complication rates for tissue sealants were 14.8% for no sealant, 18.7% for Tisseel, and 50% for DuraSeal. Nine patients were treated with the combination of Durepair and DuraSeal and this subgroup had a 56% complication rate.

Conclusions. Complication rates after CM-I decompression may be dependent on the dural graft with or without the addition of tissue sealant. The complication rate at the authors’ institution approximately doubled following the adoption of a different graft product. Tissue sealants used in combination with a dural substitute to augment a duraplasty may increase the risk of aseptic meningitis and/or CSF leak. The mechanism of the apparent increased inflammation with this combination remains under investigation.

Spine 2011;36:E1080–E1085.

Biomechanical cadaveric studies have suggested adequate spinous process strength to support placement of interspinous process spacers (IPS). Postoperative spinous process fractures have been reported in one%—to 5.8% of patients in previous series based on routine biplanar radiographic evaluation. However, most fractures occur between the base and midportion of the spinous process in an area that is typically diffi cult to visualize on plain radiographs due to device design.

Methods. All patients underwent preoperative biplanar plain radiographs and computed tomography (CT) of the lumbar spine to confirm anatomy favorable for IPS placement and rule out fracture or spondylolysis. Postoperatively, all patients underwent repeat CT imaging within six months of surgery, biplanar radiographs at two weeks, six weeks, three months, six months, and one year. All studies were reviewed independently by a neuroradiologist and two orthopedic spine surgeons.

Results. Fifty implants (38 L4–5, 12 L3–4) were placed in 38 patients who completed follow-up and were included in final analysis. Three IPS designs were included (34 Medtronic X-STOP titanium, 8 X-STOP PEEK, 8 Lanx Aspen). Postoperative CT revealed 11 nondisplaced spinous process fractures in 11 patients (28.9% of patients, 22% of levels). Five fractures were associated with mild to moderate lumbar back pain and six fractures were asymptomatic. No patient reported a traumatic incident. No fracture was identifiable on plain radiographs. One fracture displaced during follow-up evaluation. Three patients underwent IPS removal and laminectomy. Three fractures healed by CT in one year. Overall, patients with fractures tended toward poorer outcomes by Zurich Claudication Questionnaire (ZCQ) (28.5% vs. 34.8% improvement in symptom severity, P=  0.496; 21.4% vs. 30.7% improvement in physical function, P = 0.199) and tended toward lower satisfaction rates (50% vs. 73.7%, P = 0.24) at one year compared to patients without fracture.

Conclusion. Interspinous process spacer surgery appears associated with a higher rate of early postoperative spinous process fracture than previously reported. In all cases, in this series, plain radiographs were inadequate to identify fractures because all fractures were initially minimal or nondisplaced, many patients were osteopenic, and the metallic wings of the devices often obscured fractures. Moreover, in most patients, fractures were associated with mild or no acute localized pain. This study suggests that unrecognized spinous process fracture may be responsible for a signifi cant number of patients who experience unsatisfactory outcome after IPS surgery. CT imaging is required to identify the vast majority of such fractures.

J Neurosurg 114:1544–1568, 2011. DOI: 10.3171/2010.10.JNS09406

The development of endoscopic endonasal approaches, albeit in the early stages, represents part of the continuous evolution of skull base surgery. During this early period, it is important to determine the safety of these approaches by analyzing surgical complications to identify and eliminate their causes.

Methods. The authors reviewed all perioperative complications associated with endoscopic endonasal skull base surgeries performed between July 1998 and June 2007 at the University of Pittsburgh Medical Center.

Results. This study includes the data for the authors’ first 800 patients, comprising 399 male (49.9%) and 401 female (50.1%) patients with a mean age of 49.21 years (range 3–96 years). Pituitary adenomas (39.1%) and meningiomas (11.8%) were the 2 most common pathologies. A postoperative CSF leak represented the most common complication, occurring in 15.9% of the patients. All patients with a postoperative CSF leak were successfully treated with a lumbar drain and/or another endoscopic approach, except for 1 patient who required a transcranial repair. The incidence of postoperative CSF leaks decreased significantly with the adoption of vascularized tissue for reconstruction of the skull base (< 6%). Transient neurological deficits occurred in 20 patients (2.5%) and permanent neurological deficits in 14 patients (1.8%). Intracranial infection and systemic complications were encountered and successfully treated in 13 (1.6%) and 17 (2.1%) patients, respectively. Seven patients died during the 30-day perioperative period, 6 of systemic illness and 1 of infection (overall mortality 0.9%).

Conclusions. Endoscopic endonasal skull base surgery provides a viable median corridor based on anatomical landmarks and is customized according to the specific pathological process. This corridor should be considered as the sole access or may be combined with traditional approaches. With the incremental acquisition of skills and experience, endoscopic endonasal approaches have an acceptable safety profile in select patients presenting with various skull base pathologies.

Eur Spine J (2011) 20:58–64. DOI 10.1007/s00586-010-1493-8

The objective of the study was to demonstrate the clinical characteristics of dural tears during percutaneous endoscopic lumbar discectomy (PELD) and to discuss how to prevent this unintended complication.

The study used data from 816 consecutive patients who underwent PELD between 2003 and 2007. A total of nine patients (1.1%) experienced symptomatic dural tears. The clinical outcomes were evaluated using the visual analogue scale (VAS), the Oswestry disability index (ODI), and modified MacNab criteria. Intractable radicular pain was the most common symptom, while classical manifestations, such as CSF leakage or wound swelling, were rare. In three of the nine cases, the dural tears were detected intraoperatively, while the remaining six cases were not recognized during the procedure. Among the unrecognized patients, two patients were found with nerve root herniation causing profound neurological deficits. All patients were managed by secondary open repair surgeries. The mean follow-up period was 30.8 months. The mean VAS of radicular leg pain improved from 8.3 to 2.6, and that of back pain improved from 4.1 to 2.6. The mean ODI improved from 69.6 to 29.2%. The final outcomes were excellent in one, good in five, fair in one, and poor in two patients. As application of the endoscopic procedure has been broadened to more complex cases, the risk of dural tears may increase.

Unrecognized dural tear with nerve root herniation may cause permanent neurological sequelae. Accurate information and proper technical considerations are essential to prevent this unpredictable complication.

Childs Nerv Syst. DOI 10.1007/s00381-010-1339-z

As the number of endoscopic third ventriculostomy (E3V) operations increase, new rare complications are encountered. In this article, a complication caused by bone particles that migrated into the third ventricle will be described. Additionally, the methods of avoidance as well as the necessity of a new approach will be discussed.

Methods After the video images of the first and second operations of a patient who was subjected to E3V twice were compared, it was discovered that one of the bone particles within the ventricle had occluded the ostium after the second operation. Most of the bones were removed and their pathological investigations were performed.

Results Video images of the patient, surgical observations of the second operation, emergence of the time of dysfunction, and other similar cases in the literature were assessed, and it was concluded that the bones that localized intraventricularly were living tissues.

Discussion Abandoning usage of bone dust for sealing burr holes is a solution to avoid this complication. In addition, it should be kept in mind that intraventricular bone particles might grow and lead to obstructions. If such particles are detected, removal of the bones in certain locations before formation of neovascularization can be an option.

Neurosurgery 67:1396–1403, 2010 DOI: 10.1227/NEU.0b013e3181f1ec73

Fusion at the craniovertebral junction is performed to treat instability of the upper cervical spine and occiput. The literature consists exclusively of case series in which complication rate and avoidance are variably addressed.

OBJECTIVE: To describe the rates of various complications encountered during craniocervical fusions and discuss preoperative and perioperative strategies useful for risk reduction. METHODS: A computerized search of PubMed for literature on craniocervical fusion and other upper cervical fusions was performed. Keywords used in the search included: occipitocervical fusion, odontoid screw, atlantoaxial fusion, with and without complications, anterior fixation, lateral mass screw, transarticular screw, halo, vertebral artery injury, and odontoid fracture. References were limited to studies on human subjects. Other sources were identified from the reference lists of relevant publications.

RESULTS: Twenty-two reports described data derived from 2274 procedures analyzed for complications. The most commonly encountered perioperative complications were related to instrumentation failure after nonunion with rates as high as 7% during occipitocervical fusion and 6.7% during atlantoaxial fusion. Other commonly encountered complications included injury to the vertebral artery (1.3%-4.1% during placement of C1-C2 transarticular screws, most commonly in the case of high-riding vertebral artery), dural tears, and wound infection.

CONCLUSION: Occipitocervical or atlantoaxial fusion procedures can be performed with low morbidity. Safety is enhanced with appropriate preoperative assessment of anatomic variants and preparation for perioperative management of complications.