David Altschul

Postoperative urinary retention in patients undergoing elective spinal surgery

OBJECTIVE Postoperative urinary retention (POUR) is a common problem leading to morbidity and an increased hospital stay. There are limited data regarding its baseline incidence in patients undergoing spinal surgery and the risk factors with which it may be associated. The purpose of this study was to evaluate the incidence of POUR in elective spine surgery patients and determine the factors associated with its occurrence. METHODS The authors retrospectively reviewed the records of patients who had undergone elective spine surgery and had been prospectively monitored for POUR during an 18-month period. Collected data included operative positioning, surgery duration, volume of intraoperative fluid, length of hospital stay, and patient characteristics such as age, sex, and medical comorbidities. Dialysis patients or those with complete urinary retention preoperatively were excluded from analysis. RESULTS Of the 397 patients meeting the study inclusion criteria, 35 (8.8%) developed POUR. An increased incidence of POUR was noted in those who underwent posterior lumbar surgery, those with benign prostatic hypertrophy (BPH), those with chronic constipation or prior urinary retention, and those using a patient-controlled analgesia pump postoperatively. An increased incidence of POUR was seen with a longer operative time but not with intraoperative intravenous fluid administration. A significant relationship between the female sex and POUR was noted after controlling for BPH, yet there was no association between POUR and diabetes or intraoperative instrumentation. Postoperative retention significantly prolonged the hospital stay. Three patients developed epidural hematomas necessitating operative reexploration, and while they experienced POUR, they also developed the full constellation of cauda equina syndrome. CONCLUSIONS Awareness of the risk factors for POUR may be useful in perioperative Foley catheter management and in identifying patients who need particular vigilance when they are due to void postprocedure. A greater understanding of POUR may also prevent longer hospital stays in select at-risk patients. Postoperative retention is rarely caused by a postoperative cauda equina syndrome due to epidural hematoma, which is also associated with saddle anesthesia, leg pain, and weakness, yet the delineation of isolated POUR from this urgent complication is necessary for optimal patient care.

Ruptured anterior spinal artery aneurysm from a herniated cervical disc. A case report and review of the literature.

Background: Subarachnoid hemorrhage (SAH) caused by a ruptured cervical anterior spinal artery aneurysm is extremely rare and in the setting of cervical spondylosis. This case presentation reviews the diagnosis, management, and treatment of such aneurysms. Case Presentation: An 88-year-old female presented with the worst headache of her life without focal deficits. She was found to have diffuse SAH in the basal cisterns extending inferiorly down the spinal canal. Review of the neurodiagnostic images revealed an anterior spinal artery aneurysm in the setting of cervical spondylosis. Conclusions: Clinicians should be suspicious of cervical spondylosis as a rare etiology for an SAH when cerebral angiograms prove negative for intracranial aneurysms.

Computed tomography-guided lumbar drain placement: Technical note

The authors describe a technique for lumbar drain placement using CT guidance. Midline or paramidline interlaminar approaches to the thecal sac can be used. The major advantage to CT guidance is direct visualization of the needle tip in relation to the thecal sac. This technical approach is a safe and rapid alternative to fluoroscopic guidance for the placement of lumbar drains in patients in whom standard lumbar drain placement techniques have failed.

Comparison of the Prevalence of Ruptured and Unruptured Cerebral Aneurysms in a Poor Urban Minority Population

BACKGROUND Most ruptured cerebral aneurysms are small (<7 mm). Evidence suggests low rupture rates for such lesions (<1% per year). Population studies demonstrate a prevalence rate of 3.2%. This study simultaneously estimates the prevalence of aneurysms in a single geographic population while reporting the observed rate of aneurysmal subarachnoid hemorrhage (aSAH) in the same geographic region composed of a poor urban minority demographic. METHODS This is an institutional review board-approved, Health Insurance Portability and Accountability Act of 1996-compliant retrospective study performed between 2005 and 2011 at a single center. Part 1 used the electronic medical record to identify all patients with a magnetic resonance angiography demonstrating a cerebral aneurysm. Part 2 used the electronic medical record to identify all patients from the same geographic area presenting with aSAH during the study period. RESULTS A total of 11,160 subjects had a magnetic resonance angiography from the study area. In this group, 422 intradural cerebral aneurysms were incidentally discovered. Ninety-one percent were less than 10 mm (mean 5.49, standard deviation 4.6). Twenty-one percent were aneurysms of the anterior communicating artery complex. Fourteen percent were of posterior communicating artery origin. A total of 237 patients had aSAH. Ninety-two percent of the aneurysms were less than 10 mm (mean 6 mm, standard deviation 3.2 mm). Both groups were composed of poor urban minority patients. CONCLUSIONS The observed annual rate of rupture of small anterior circulation aneurysms in this study was .06%-.15% per year. The extrapolated population prevalence of such aneurysms (4.0%-1.5%) may explain the observed rate of rupture of these small aneurysms in a poor urban minority population.

Radiolucent Skull Clamps for Intra-Operative Imaging: A Technical Note

Conventionally, surgery and procedural-based radiology are performed on different premises. With advances in imaging technology, the operating room is rapidly being transformed into an intraoperative imaging suite. Diagnostic imaging in conjunction with surgery has great utility and by all accounts has great future potential. During the last decade, cone beam computed tomography (CT) scanners have been introduced and have made intraoperative imaging more feasible because these scanners can be made less bulky. The current usefulness of intraoperative magnetic resonance imaging (MRI) or CT for neurosurgery, however, is impaired by the lack of completely radiolucent skull clamps, causing image artifacts. Metal artifacts are particularly problematic, given that they lead to a considerably higher image quality degradation factor for cone beam CT scanners than for conventional CT scanners. Here, we describe our experience with near-radiolucent skull clamps and their associated problems and discuss future improvements to facilitate high-quality image guidance in the field of neurosurgery.

Somatosensory evoked potential monitoring detection of carotid compression during ACDF surgery in a patient with a vascularly isolated hemisphere

The authors report herein a case of anterior cervical discectomy and fusion (ACDF) surgery in which findings on somatosensory evoked potential (SSEP) monitoring led to the correction of carotid artery compression in a patient with a vascularly isolated hemisphere (no significant collateral blood vessels to the carotid artery territory). The amplitude of the cortical SSEP component to left ulnar nerve stimulation progressively decreased in multiple runs, but there were no changes in the cervicomedullary SSEP component to the same stimulus. When the lateral (right-sided) retractor was removed, the cortical SSEP component returned to baseline. The retraction was then intermittently relaxed during the rest of the operation, and the patient suffered no neurological morbidity. Magnetic resonance angiography demonstrated a vascularly isolated right hemisphere. During anterior cervical spine surgery, carotid artery compression by the retractor can cause hemispheric ischemia and infarction in patients with inadequate collateral circulation. The primary purpose of SSEP monitoring during ACDF surgery is to detect compromise of the dorsal column somatosensory pathways within the cervical spinal cord, but intraoperative SSEP monitoring can also detect hemispheric ischemia. Concurrent recording of cervicomedullary SSEPs can help differentiate cortical SSEP changes due to hemispheric ischemia from those due to compromise of the dorsal column pathways. If there are adverse changes in the cortical SSEPs but no changes in the cervicomedullary SSEPs, the possibility of hemispheric ischemia due to carotid artery compression by the retractor should be considered.

Novel double catheter technique with detachable microcatheter for the treatment of arteriovenous malformations: A technical note

Background: Onyx has improved the safety and efficacy of endovascular treatment in the management of cerebral arteriovenous malformations (AVMs). However, during injection inadvertent reflux around the delivery microcatheter into important normal arterial branches remains a major challenge. Methods: We describe a new double arterial catheterization technique using a detachable tip microcatheter in conjunction with a second microcatheter to form a proximal antireflux Onyx plug. This novel technique allows for increased amounts of Onyx to be steadily injected while avoiding dangerous backflow in the treatment of AVMs. Results: The patient tolerated the procedure well without changes in hemodynamics. Using the novel double catheter technique, a significant portion of the AVM was embolized and the patient had no complications postoperatively. Conclusions: The novel double catheter technique with a detachable microcatheter is a safe and effective technique to increase the amount of Onyx embolization material into the AVM nidus.