Review of psychiatric comorbidities and their associations with opioid use in elective lumbar spine surgery.

The opioid epidemic is an ongoing concern in the United States and efforts to ameliorate this crisis are underway on multiple fronts. Opiate use is an important consideration for patients undergoing lumbar spine surgery with concurrent psychiatric diagnoses and more information is needed regarding the factors involved in these patients. That information may help guide opioid prescribing practices for individual patients with certain psychiatric conditions that are undergoing these procedures. This study was done to identify psychiatric conditions that are associated with preoperative and postoperative opioid use in this cohort of veteran patients undergoing elective lumbar spine surgery.A 3 month preoperative and 3 month postoperative chart review was conducted on 25 patients per year who underwent elective lumbar spine surgery over a 16-year period at the Veterans Affairs Nebraska-Western Iowa Healthcare Center (n = 376 after exclusion criteria applied). The association between psychiatric comorbidities and use of opioids during the 90-day period after surgery was assessed using a linear model that adjusted for surgical type, opioid use prior to surgery, and other relevant comorbidities.Patients are more likely to use opioids preoperatively if they have major depression (P = .02), hepatitis C (P = .01), or musculoskeletal disorders (P = .04). PTSD (P = .02) and lumbar fusion surgery (P < .0001) are associated with increased postoperative use, after adjusting for preoperative use and other comorbidities.Certain psychiatric comorbidities are significantly correlated with opioid use for this cohort of lumbar spine surgery patients in the preoperative and postoperative periods. Awareness of an individual's psychiatric comorbidity burden may help guide opioid prescription use.

Effect of Protein Concentration on the Flow of Cerebrospinal Fluid Through Shunt Tubing.

BACKGROUND: Protein levels in cerebrospinal fluid (CSF) are commonly thought to be related to sterile shunt malfunction. OBJECTIVE: To investigate the relationship between protein concentration and flow through CSF shunt tubing and a shunt valve. METHODS: New and explanted shunt catheters were tested with and without a shunt valve attached at various protein concentrations. The protein concentrations used were 0.5, 2, 5, and 10 g/L. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour, and then the change in pressure between the proximal and distal end of the catheter was measured and recorded. The resistance to flow was calculated for new and explanted catheters for adult shunt systems, as well as with the addition of a programmable siphon control valve. The resistance was examined after the addition of various protein concentrations to a normal CSF solution. RESULTS: Both new and explanted catheters exhibited a decrease in the resistance to flow with higher concentrations of protein. CONCLUSION: In our laboratory setting, there was decreased resistance of adult CSF shunt catheters with and without a valve as the concentration of protein in the CSF increased. The decrease in the resistance of CSF shunt catheters with the addition of protein to the CSF may be related to the lowering of surface tension. This is the first study to examine the effects of varying protein concentrations across different lengths of shunt tubing for both new and explanted catheters.

Analysis of adjacent segment degeneration with laminectomy above a fused lumbar segment.

Although recent data suggests that lumbar fusion with decompression contributes to some marginal acceleration of adjacent segment degeneration (ASD), few studies have evaluated whether it is safe to perform a laminectomy above a fused segment. This study investigates the hypothesis that laminectomy above a fused lumbar segment does not increase the incidence of ASD, and assesses the benefits and risks of performing a laminectomy above a lumbar fusion. A retrospective review of 171 patients who underwent decompression and instrumented fusion of the lumbar spine was performed to analyze the association between ASD and laminectomy above the fused lumbar segment. Patients were divided into two groups - one group with instrumented fusion alone and the other group with instrumented fusion plus laminectomy above the fused segment. Of the 171 patients, 34 underwent additional decompressive laminectomy above the fused segment. There was a significant increase in ASD incidence as well as progression of ASD grade in both groups. There was no significant increase in ASD in patients with decompressive laminectomy above the fused lumbar segment compared to patients with laminectomy limited to the fused segment. This retrospective review of 171 patients who underwent decompression and instrumented fusion with follow-up radiographs demonstrates that laminectomy decompression above a fused segment does not significantly increase radiographic ASD. There is, however, a significant increase in ASD over time, which was observed throughout the entire cohort likely representing a natural progression of lumbar spondylosis above the fusion segment.

Flow characteristics of cerebrospinal fluid shunt tubing.

OBJECT: Cerebrospinal fluid shunt systems malfunction for a multitude of reasons, including malpostitioning, obstruction of the ventricular or distal catheter, obstruction of the shunt valve, and catheter disruptions or disconnections. The goal of this study was to examine the hydrodynamic resistance and flow in new and explanted catheters and also in catheters with 1 or 2 straight connectors. METHODS: Explanted catheters of multiple lengths, 2-piece catheters, 3-piece catheters, and new catheters were attached to a proximal and distal manometer. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour; then the change in pressure between the proximal and distal end of the catheter was measured. RESULTS: The resistance to flow was calculated for new, never-implanted catheters and compared with the resistance of explanted distal shunt catheters. The resistance of the new catheters was examined after the addition of 1 and 2 straight connectors. Explanted catheters exhibited a slight increase in the resistance to flow of artificial CSF compared with new catheters. Two-piece and 3-piece catheters had a significant increase in resistance to flow compared with new catheters. For all catheters, resistance to flow increased as length increased (new, p = 0.01; explanted, p = 0.009; 1 connector, p = 0.01; 2 connectors, p = 0.03). In this paper, effective diameter is defined as the available cross-sectional area of catheter contacted by the artificial CSF. For new and explanted catheters, a decrease in the effective diameter of the catheter was associated with an increase in the resistance to flow of artificial CSF (new, p = 0.1083; explanted, p = 0.0091). However, after the addition of 1 or 2 connectors, an inverse trend was observed: resistance to flow increased with effective diameter. CONCLUSIONS: There appears to be some increase in resistance of CSF shunt catheters as they age, altering flow dynamics. In addition, the use of straight connectors within a CSF shunt system increases the resistance to flow of artificial CSF within the shunt system. The increase in resistance appears to be related to the duration of implantation and the length of the catheter and inversely related to the diameter of the catheter. This increase in resistance may be related to sterile shunt malfunction. The addition of straight connectors is associated with a significant increase in resistance in comparison with catheters without connectors (p = 0.005).

Radiographic PEEK double-lucency finding after anterior cervical discectomy and fusion with local autograft and PEEK spacer: a preliminary study.

Anterior cervical discectomy and fusion (ACDF) is considered a standard neurosurgical treatment for cervical degenerative disc disease, but the methods for determining fusion after ACDF that involves the use of a polyetheretherketone (PEEK) cage are not well defined. The authors examine an image finding called "PEEK double lucency" that may be useful in identifying fusion. This finding was studied to determine if it would be helpful in identifying fusion on radiographs obtained in 148 patients who underwent an ACDF in which a PEEK cage was filled with local autograft bone (bone spurs in the present cases). The presence of a PEEK double lucency was discovered during review of the plain radiographs and defined as a complete radiolucent ring around the titanium markers within the PEEK cage. In total, 178 spinal levels were examined. Of the 356 (2 for each of the 178 levels) titanium portions examined, the PEEK double lucency was present in 323 or 91% of the titanium portions of the PEEK cages for the patients with complete fusion. The authors conclude that the radiolucent feature of the PEEK cage, which produces the image finding PEEK double lucency, aids in the determination of fusion.

Single-dose vs multiple-dose antibiotic prophylaxis in instrumented lumbar fusion--a prospective study.

BACKGROUND: This prospective investigation was designed to determine if the postoperative infection rate in instrumented lumbar spinal fusion is affected by postoperative antibiotic use. METHODS: Two hundred sixty-nine patients were randomized into either a preoperative only protocol or preoperative with an extended postoperative antibiotic protocol. The preoperative only protocol received a single dose of cefazolin IV. The extended postoperative antibiotic protocol received the same preoperative dose plus postoperative cefazolin IV every 8 hours for 3 days followed by oral cephalexin every 6 hours for 7 days. Because of untoward drug reaction or deviation from the antibiotic protocol, 36 of the 269 patients were eliminated from the study. Therefore, 233 patients completed the entire study. RESULTS: There was no significant difference in infection rates between the 2 antibiotic protocols. The postoperative infection rates were 4.3% for the preoperative only protocol and 1.7% for the preoperative with extended antibiotic protocol. The overall postoperative infection rate was 3%. However, 5 variables of blood transfusion, electrophysiologic monitoring, increased height, increased weight, and increased body mass index appeared to demonstrate a trend toward increase in infection rate. Increased tobacco use trended toward a lower infection rate. CONCLUSION: Statistical significance was not proven in this prospective study comparing single-dose preoperative antibiotic protocol vs preoperative with an extended postoperative antibiotic protocol. A larger study of 1400 patients would possibly provide more statistically significant information.

Benign extracerebral fluid collections in infancy: clinical presentation and long-term follow-up.

OBJECT: Benign extracerebral fluid collections are common in infants, but there are unanswered questions regarding presentation and long-term outcome. This study was undertaken to establish head size at birth, head size at presentation, head growth over time, history of presentation, indications for surgery, and long-term results. METHODS: Cases of benign extracerebral fluid collections in infancy were retrospectively reviewed. Data pertaining to clinical presentation, progress, and long-term follow-up were evaluated. Patients were divided into two groups on the basis of the presence or absence of increased signal intensity of fluid in the extracerebral space on T1-weighted magnetic resonance images. Group 1 consisted of 39 patients who had benign extracerebral fluid collections without any subdural collections. Group 2 consisted of nine patients who had a chronic subdural hematoma or hygroma without a history of trauma and had generous subarachnoid spaces and/or a history of premature birth. Patients were observed for an average of 49 months. RESULTS: Group 1 included 39 patients (ages at presentation 3-12 months); the most common presentation in this group was macrocephaly (28 cases). Of those Group 1 cases in which data regarding gestational age at birth were available, 15 births were either severely or mildly premature and 14 were full term. Of those Group 1 patients with adequate data, 14 had an occipitofrontal circumference (OFC) in the 50th to 98th percentile at birth and two had OFCs greater than the 98th percentile. Measurements obtained at 24 months of age were available for 18 Group 1 patients: OFC was at approximately the 98th percentile in eight (all eight born at full term) and more than 1 cm larger than the 98th percentile in 10. Head growth in Group 1 patients continued to decrease, approaching the 98th percentile after 24 months of age. Only three of the 39 patients in Group 1 required shunt placement. Of the 33 Group 1 patients for whom long-term follow-up was available, 30 were developing normally, and three had mild developmental delays. Group 2 included nine patients (ages at presentation 3-7 months); the most common presentations were large head (three patients) and seizures (three patients). Data concerning gestational age at birth were available in eight Group 2 cases: birth was severely premature in four and gestation was full term in four. Five Group 2 patients were treated surgically-two with subduroperitoneal (SDP) shunt placement, two with subdural punctures, and one with subdural punctures and SDP shunt placement. Adequate follow-up information was available in eight of nine Group 2 cases; all eight patients were found to be developing normally. CONCLUSIONS: Group 1 patients usually had a normal head size at birth, they rarely required shunt placement, their head growth eventually leveled off toward the 98th percentile line, and their outcomes were generally good. Although five of nine Group 2 patients required subdural punctures and/or SDP shunt placement, that group of patients also developed well. Infants with nontraumatic subdural hematomas or hygromas, presumably associated with benign extracerebral fluid collections, can often experience significant resolutions of the hematoma or hygroma within several months without surgical treatment.

Abdominal pseudocyst: predisposing factors and treatment algorithm.

Abdominal pseudocyst (APC) is an uncommon complication of ventriculoperitoneal shunts. Various predisposing factors have been attributed to it, including the presence of infection and multiple shunt revisions. We reviewed the records of shunt revisions performed over a 20-year period. During that time, 64 cases of APC were found in 36 patients. The records were then reviewed for the presence of infection, history of necrotizing enterocolitis, prior abdominal surgery, and treatment performed. Of the cases of APC, 46 were primary and 18 were recurrent. A history of prior abdominal surgery other than shunt revision was found in 47% of patients and a history of necrotizing enterocolitis was found in 19% of patients. The average number of prior shunt revisions was 4.1 per patient. Shunt infection as defined by positive cultures of either cerebrospinal fluid or abdominal fluid was present in only 23% of cases of APC. A history of prior shunt infection was present in 30% of patients. Infection was treated by shunt removal, external ventricular drainage, and appropriate antibiotics. After the infection was cleared or if no infection was present, treatment consisted of: (1) repositioning the distal catheter into the peritoneum, (2) repositioning the distal catheter into the pleural space, the atrium, or the gallbladder, (3) exploratory laparotomy with lysis of adhesions and repositioning the peritoneal catheter, (4) APC aspiration only, or (5) shunt removal or disconnection. Because of the complexity of APC management, we analyzed the outcomes of our cases and outlined an algorithm to simplify this process.

Stretching and breaking characteristics of cerebrospinal fluid shunt tubing.

OBJECT: Cerebrospinal fluid (CSF) shunt system malfunction due to silastic tubing fracture necessitates revision surgery in shunt-dependent individuals. The goal of this study was to examine the mechanical stretching and breaking characteristics of new and used CSF shunt tubing catheters to determine if any inherent physical properties predispose the tubing to fracture. METHODS: Fifty-millimeter segments of new and retrieved (used) CSF shunt tubing were stretched to 120 mm in a hydraulic press to determine modulus values (modulus = stress/strain) and to measure permanent tubing deformation imparted by the applied stress and strain. Similar 50-mm tubing segments were also stretched in an electromechanical material testing system until fracture occurred; the force and strain needed to break the tubing was recorded at the time of failure. The results demonstrate that shunt tubing with a greater cross-sectional area requires greater force to fracture, and that catheters become weaker the longer they are implanted. Barium-impregnated shunt tubing, compared with translucent tubing. appears to require less applied stress and strain to break and may fracture more easily in vivo. The variety of modulus values obtained for the new catheters tested indicates that the various companies may be using materials of different quality in tubing manufacture. CONCLUSIONS: A CSF shunt catheter design that incorporates tubing with a greater cross-sectional area may lead to fewer fractures of indwelling catheters and a reduction in shunt revision surgery.