Impact of Anxiety During Hospitalization on the Clinical Outcome of Patients With Osteoporotic Thoracolumbar Vertebral Fracture

STUDY DESIGN

Multicenter prospective cohort study.

OBJECTIVES

Anxiety in combination with osteoporotic vertebral compression fractures (OVCFs) of the spine remains understudied. The purpose of this study was to analyze whether anxiety has an impact on the short-term functional outcome of patients with an OVCF. Furthermore, a direct impact of the fracture on the patient's anxiety during hospitalization should be recognized.

METHODS

All inpatients with an OVCF of the thoracolumbar spine from 2017 to 2020 were included. Trauma mechanism, analgetic medication, anti-osteoporotic therapy, timed-up-and-go test (TuG), mobility, Barthel index, Oswestry-Disability Index (ODI) and EQ5D-5L were documented.For statistical analysis, the U test, chi-square independence test, Spearman correlation, General Linear Model for repeated measures, Bonferroni analysis and Wilcoxon test were used. The item anxiety/depression of the EQ5D-5L was analyzed to describe the patients' anxiousness.

RESULTS

Data from 518 patients from 17 different hospitals were evaluated. Fracture severity showed a significant correlation (r = .087, P = .0496) with anxiety. During the hospital stay, pain medication (P < .001), anti-osteoporotic medication (P < .001), and initiation of surgical therapy (P < .001) were associated with less anxiety. The anxiety of a patient at discharge was negatively related to the functional outcomes at the individual follow-up: TuG (P < .001), Barthel index (P < .001), ODI (P < .001) and EQ5D-5L (P < .001).

CONCLUSIONS

Higher anxiety is associated with lower functional outcome after OVCF. The item anxiety/depression of the EQ5D-5L provides an easily accessible, quick and simple tool that can be used to screen for poor outcomes and may also offer the opportunity for a specific anxiety intervention.

Effect of subsequent vertebral body fractures on the outcome after posterior stabilization of unstable geriatric fractures of the thoracolumbar spine

PURPOSE

The purpose of this study was analyzing the effect of subsequent vertebral body fractures on the clinical outcome in geriatric patients with thoracolumbar fractures treated operatively.

METHODS

Retrospectively, all patients aged ≥ 60 with a fracture of the thoracolumbar spine included. Further inclusion parameters were acute and unstable fractures that were treated by posterior stabilization with a low to moderate loss of reduction of less than 10°. The minimal follow-up period was 18 months. Demographic data including the trauma mechanism, ASA score, and the treatment strategy were recorded. The following outcome parameters were analyzed: the ODI score, pain level, satisfaction level, SF 36 score as well as the radiologic outcome parameters.

RESULTS

Altogether, 73 patients were included (mean age: 72 years; 45 women). The majority of fractures consisted of incomplete or complete burst fractures (OF 3 + 4). The mean follow-up period was 46.6 months. Fourteen patients suffered from subsequent vertebral body fractures (19.2%). No trauma was recordable in 5 out of 6 patients; 42.8% of patients experienced a low-energy trauma (significant association: p < 0.01). There was a significant correlation between subsequent vertebral body fracture and female gender (p = 0.01) as well as the amount of loss of reduction (p = 0.02). Thereby, patients with subsequent vertebral fractures had significant worse clinical outcomes (ODI: 49.8 vs 16.6, p < 0.01; VAS pain: 5.0 vs 2.6, p < 0.01).

CONCLUSION

Patient with subsequent vertebral body fractures had significantly inferior clinical midterm outcome. The trauma mechanism correlated significantly with both the rate of subsequent vertebral body fractures and the outcome. Another risk factor is female gender.

[Thoracolumbar spinal fractures in the elderly : Classification and treatment]

Thoracolumbar fractures in the elderly are frequently associated with osteoporosis. Osteoporosis can cause fractures or be a significant comorbidity in traumatic fractures. The OF classification is based on conventional X‑ray, computed tomography (CT) scan and magnetic resonance imaging (MRI). It is easy to use and provides a clinically relevant classification of the fractures. Therapeutic decisions are made based on the clinical and radiological situation by using the OF score. The score takes the current clinical situation including patient-specific comorbidities into consideration. The treatment recommendations are based on an expert consensus opinion and include conservative and operative options. If surgery is indicated, vertebral body augmentation, percutaneous stabilization and even open surgery can be used.

Neutropenia following Perioperative Intraperitoneal Chemotherapy

Introduction

The purpose of this retrospective report was to evaluate clinical features associated with profound neutropenia in patients with peritoneal carcinomatosis who were treated with heated intraoperative intraperitoneal chemotherapy (HIIC) followed by early postoperative intraperitoneal chemotherapy (EPIC). Common clinical denominators for significant neutropenia were analyzed.

Materials and Methods

A retrospective study of all available clinical data of six patients with postoperative neutropenia out of a total of 242 was undertaken. All patients underwent cytoreductive surgery, HIIC with mitomycin C (n = 4) or cisplatin (n = 1) and EPIC with 5-fluorouracil (5-FU) for 4 (n = 1) or 5 (n = 5) days.

Results

All six patients presented with hematologic toxicity of WHO criteria grade 4; four of them died postoperatively. Two of the patients who died, and one who did not die, developed bowel perforations. Five patients had prior chemotherapy with 5-FU; three of them had toxic side effects. All patients were overweight, and three patients were anemic preoperatively. The neutropenia presented with fever, leukopenia and thrombocytopenia on postoperative days 10–15. The leukocyte count courses showed a pattern suggesting the 5-FU as the cause of leukopenia. There was no consistent warning signal for predicting severe neutropenia.

Discussion

Neutropenia following cytoreductive surgery combined with HIIC and EPIC has a high mortality (66%). Patients who are at special risk and should have a dose reduction include patients who had toxicities from prior chemotherapy, who present with obesity and anemia. The groups have an increased risk of developing postoperative profound neutropenia. This condition can result in a prohibitively high mortality and morbidity rate. Therefore, reduced doses of chemotherapy in selected patients are necessary to prevent this condition from developing.

[Cement augmentation of pedicle screws : Pros and cons]

Cement augmentation of pedicle screws biomechanically increases screw purchase in the bone. However, clinical complications may occur. The pros and cons of the technique are discussed from different clinical perspectives.

[The AOSpine Classification of Thoraco-Lumbar Spine Injuries]

Optimal treatment of injuries to the thoracolumbar spine is based on a detailed analysis of instability, as indicated by injury morphology and neurological status, together with significant modifying factors. A classification system helps to structure this analysis and should also provide guidance for treatment. Existing classification systems, such as the Magerl classification, are complex and do not include the neurological status, while the TLICS system has been accused of over-simplifying the influence of fracture morphology and instability. The AOSpine classification group has developed a new classification system, based mainly upon the Magerl and TLICS classifications, and with the aim of overcoming these drawbacks. This differentiates three main types of injury: Type A lesions are compression lesions to the anterior column; Type B lesions are distraction lesions of either the anterior or the posterior column; Type C lesions are translationally unstable lesions. Type A and B lesions are split into subgroups. The neurological damage is graded in 5 steps, ranging from a transient neurological deficit to complete spinal cord injury. Additional modifiers describe disorders which affect treatment strategy, such as osteoporosis or ankylosing diseases. Evaluations of intra- and inter-observer reliability have been very promising and encourage the introduction of this AOSpine classification of thoracolumbar injuries to the German speaking community.

Experimentelle Spondylodese der Schafshalswirbelsäule Teil 1: Der Effekt des Cage-Designs auf die intervertebrale Fusion

INTRODUCTION

There has been a rapid increase in the use of interbody fusion cages as an adjunct to spondylodesis, although experimental data are lacking. A sheep cervical spine interbody fusion model was used to determine the effect of different cage design parameters (endplate-implant contact area, maximum contiguous pore) on interbody fusion.

MATERIAL AND METHOD

IN VITRO EVALUATION: 24 sheep cadaver specimens (C2-C5) were tested in flexion, extension, axial rotation, and lateral bending with a nondestructive flexibility method using a nonconstrained testing apparatus. Four different groups were examined: (1) control group (intact) ( n=24), (2) autologous tricortical iliac crest bone graft ( n=8), (3) Harms cage ( n=8), and (4) SynCage-C ( n=8). IN VIVO EVALUATION: 24 sheep underwent C3/4 discectomy and fusion: group 1: autologous tricortical iliac crest bone graft ( n=8), group 2: Harms cage filled with autologous cancellous iliac crest bone grafts ( n=8), and group 3: SynCage-C filled with autologous cancellous iliac crest bone grafts ( n=8). Radiographic scans were performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks, respectively. At the same time points, disc space height (DSH), height index (HI), intervertebral angle (IVA), and endplate angle (EA) were measured. After 12 weeks the animals were killed and fusion sites were evaluated using biomechanical testing in flexion, extension, axial rotation, and lateral bending. Additionally, histomorphological and histomorphometrical analyses were performed.

RESULTS

Over a 12-week period the cage groups showed significantly higher values for DSH, HI, IVA, and EA compared to the bone graft. In vivo stiffness was significantly higher for the tricortical iliac crest bone graft and Harms cage than in vitro stiffness. However, there was no difference between in vitro and in vivo stiffness of the SynCage-C. Histomorphometrical evaluation showed a more progressed bone matrix formation in the Harms cage group than in both other groups.

CONCLUSION

The parameter endplate-implant contact area was not able to determine subsidence of cages. In contrast, the maximum contiguous pore of a cage significantly correlates with interbody bone matrix formation inside the cage. Additionally, there was no correlation between in vitro and in vivo stiffness of interbody fusion cages. Therefore, biomechanical in vitro studies are not able to determine in vivo outcome of fusion cages. Animal experimental evaluations of interbody fusion cages are essential prior to clinical use.

[Fusion criteria for cages as vertebral body replacement in thoracolumbar fractures]

BACKGROUND

No commonly accepted criteria to evaluate bony incorporation of cages as vertebral body replacement in thoracolumbar fractures exist. The goal of this study was a thorough radiological evaluation of the fusion process in posterior-anterior stabilized fractures.

PATIENTS AND METHODS

In this study 35 patients were evaluated radiologically including computed tomography (CT) scanning and bone mineral density measurement inside the cages. Correction loss, cage subsidence and tilting, bone growth in and around the cages as well as bone mineral density were assessed. Fusion grading was assessed with defined criteria (i.e. bridging bone, bone growth through the cage, stability in functional X-rays and no radiolucent lines).

RESULTS

After 12 months minor subsidence and tilting of the cages had caused significant correction loss of the basal plate angle of 2.4° on average. Of the patients 20 (57%) fulfilled the criteria for complete or incomplete fusion and 5 (14%) showed no signs of bony fusion. Bone mineral density measurements were unreliable due to metallic artefacts.

CONCLUSIONS

The advocated criteria allow accurate assessment of bony incorporation of cages. Bony incorporation can be detected in and around the cages over time; however, only 57% of patients showed signs of bony fusion after 1 year.

[Dislocation of double-threaded screws after stabilization of the odontoid process with the Knöringer technique]

A type III fracture of the odontoid process according to Anderson-D'Alonzo in a 92-year-old patient was stabilized anteriorly with two double-threaded screws using the technique of Knöringer. Postoperatively, cranial dislocation of the screws was evident and attempts to correct the screw position failed resulting in screw proximity to the brain stem. In a second revision the screws could be removed by an anterior approach and fusion was achieved by a posterior approach. Type III fractures of the odontoid process are usually stable and should be treated conservatively. In case of instability posterior stabilization techniques should be selected. Anterior osteosynthesis of the odontoid process with double-threaded screws in osteoporotic bone carries the risk of screw dislocation.

[Cervical disc herniation]

The cervical disc herniation is characterized by prolapsed nucleus pulposus material through the annulus into the spinal canal. The local mechanical or chemical irritation of neural structures typically leads to symptoms of radiculopathy, cervicocephalgia or myelopathy. Pronounced sensorimotor deficits or intractable pain constitute surgical treatment. In all other cases conservative treatment is indicated, including pain medication, active and passive physiotherapy, and local injections, respectively. Anterior cervical discectomy and interbody fusion (ACDF) is still the surgical treatment of choice. Predominantly, cages with or without plates are in use to obtain solid fusion. The implantation of a total disc replacement is a viable alternative, if no contraindications exist. Other surgical techniques may be performed in proper selected cases. The overall clinical and radiological results of both surgical and conservative treatment are good.

[Recommendations for the treatment of thoracolumbar and lumbar spine injuries]

This paper gives recommendations for treatment of thoracolumbar and lumbar spine injuries. The recommendations are based on the experience of the involved spine surgeons, who are part of a study group of the "Deutsche Gesellschaft für Unfallchirurgie" and a review of the current literature. Basics of diagnostic, conservative, and operative therapy are demonstrated. Fractures are evaluated by using morphologic criteria like destruction of the vertebral body, fragment dislocation, narrowing of the spinal canal, and deviation from the individual physiologic profile. Deviations from the individual sagittal profile are described by using the monosegmental or bisegmental end plate angle. The recommendations are developed for acute traumatic fractures in patients without severe osteoporotic disease.

[Local vertebral body destruction after migration of a nucleus replacement]

We present the case report of a 32-year-old female suffering from severe low back pain because of local vertebral body destruction at L3/4 after migration of PDN-SOLO nucleus replacement. Removal of the dislocated implant via a posterior transforaminal approach was not possible. After posterior stabilisation the implant could be salvaged from the anterior direction, but stabilisation with a vertebral body replacement was necessary.

[Vertebral body replacement in spine surgery]

Autografts and allogeneous bone grafts as well as cages are used for the reconstruction of the anterior column after corpectomy. Recently, expandable cages for vertebral body replacement have been developed. Based on our own experience, the purpose of this study was to summarize the available biomechanical and clinical data of expandable corpectomy cages and to compare it with established fixation techniques. If used correctly, expandable cages offer several surgical advantages in comparison to non-expandable cages. However there were no significant differences between the biomechanical properties of expandable and non-expandable cages. Additionally, design variations of expandable corpectomy cages did not show any significant impact on the biomechanical stability. Currently available mid-term clinical and radiological data on the treatment of fractures, metastasis and infection of the cervical, thoracic and lumbar spine demonstrated no significant difference between expandable and non-expandable cages. However, the increased stress-shielding effect of expandable cages compared to non-expandable cages might result in a deterioration of the long-term clinical outcome.

Genauigkeit der CT-basierten Navigation von Pedikelschrauben an der Brustwirbels�ule im Vergleich zur konventionellen Technik

The goal of this study was to evaluate the accuracy of CT-based computer-assisted pedicle screw insertion in the thoracic spine in patients with fractures, metastases, and spondylodiscitis compared to a conventional technique. A total of 324 pedicle screws were inserted in the thoracic spines of 85 patients: 211 screws were placed using a CT-based optoelectronic navigation system assisted by an image intensifier and 113 screws were placed with a conventional technique. Screw positions were evaluated with postoperative CT scans by an independent radiologist. In the computer-assisted group, 174 (82.5%) screws were found completely within their pedicles compared with 77 (68.1%) correctly placed screws in the conventional group ( p<0.003). Despite use of the navigation system, 1.9% of the computer-assisted screws perforated the pedicle wall by more than 4 mm. The additional use of the image intensifier helped to identify the correct vertebral body and avoided cranial or caudal pedicle wall perforations.

[Experimental fusion of the sheep cervical spine. Part II: Effect of growth factors and carrier systems on interbody fusion]

INTRODUCTION

A sheep cervical spine interbody fusion model was used to determine the effect of different carriers and growth factors on interbody bone matrix formation. The purpose of this study was to compare the efficacy and safety of combined IGF-I and TGF-beta1 application with BMP-2 application in spinal fusion. Additionally, a new poly (D, L-lactide) carrier system was compared to a collagen sponge carrier.

METHOD

Forty sheep underwent C3/4 discectomy and fusion: group 1: titanium cage ( n=8), group 2: titanium cage coated with a PDLLA carrier (n=8), group 3: titanium cage coated with a PDLLA carrier including BMP-2 ( n=8), group 4: titanium cage with a collagen carrier including BMP-2 ( n=8), and group 5: titanium cage coated with a PDLLA carrier including IGF-I and TGF-beta1 ( n=8). Blood samples, body weight, and temperature were analyzed. Radiographic scans were performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks, respectively. At the same time points, disc space height (DSH) and intervertebral angle (IVA) were measured. After 12 weeks the animals were killed and fusion sites were evaluated using functional radiographic views in flexion and extension. Quantitative computed tomographic scans (QCT) were performed to assess bone mineral density (BMD), bone mineral content (BMC), and bony callus volume (BCV). Biomechanical testing was carried out in flexion, extension, axial rotation, and lateral bending. Range of motion (ROM), neutral zone (NZ), and elastic zone (EZ) were determined. Histomorphological and histomorphometrical analyses were performed and polychrome sequential labeling was used to determine the time frame of new bone formation.

RESULTS

In comparison to the non-coated cages, all PDLLA-coated cages showed significantly higher values for BMD of the callus and bone volume/total volume ratio. In comparison to the cage groups (groups 1 and 2), the cage plus BMP-2 (groups 3 and 4) and the cage plus IGF-I and TGF-beta1 group (group 5) demonstrated a significantly higher fusion rate in radiographic findings, a higher biomechanical stability, an advanced interbody fusion in histomorphometric analysis, and an accelerated interbody fusion on fluorochrome sequence labeling. BMP-2 application by the PDLLA carrier system (group 3) demonstrated significantly higher bony callus volume than BMP-2 application by a collagen sponge carrier (group 4). The BMP-2 group (group 3) showed significantly lower residual motion on functional radiographic evaluation and higher intervertebral bone matrix formation on fluorochrome sequence labeling at 9 weeks in comparison to the IGF-I/TGF-beta1 group (group 5). In contrast, the IGF-I/TGF-beta1 group (group 5) showed a significantly higher bone mineral density of the callus than the BMP-2 group (group 3).

CONCLUSION

PDLLA coating of cervical spine interbody fusion cages as a delivery system for growth factors was effective and safe. In comparison to the collagen sponge carrier, the new PDLLA carrier system was able to improve results of interbody bone matrix formation. Both growth factors (BMP-2 and combined IGF-I and TGF-beta1) significantly accelerated results of interbody fusion. Based on these preliminary results, the combined IGF-I/TGF-beta1 application yields results equivalent to BMP-2 application at an early time in anterior sheep cervical spine fusion.

[Mechanical comparison of biodegradable intervertebral lumbar cages]

INTRODUCTION

A biodegradable interbody cage for lumbar spine fusion would be able to solve several problems associated with the use of metallic cages. In a biomechanical in vitro study using human lumbar spines three different biodegradable poly(L-lactide-co-D,L-lacitide)(PLDLLA) cages were compared to metallic cages of the same design.

MATERIAL AND METHOD

40 human cadaver lumbar specimens (L3-S1) were tested in flexion, extension, rotation, and bending with a non-destructive flexibility method using a nonconstrained testing apparatus. Seven different groups were examined: (1) control group (intact) (n = 40); (2) unstable group (after discectomy L4/5) (n = 40), (3) autologous iliac crest bone graft (n = 8), (4) BAK-Cage (n = 8), (5) BIO-Cage 1 (PLDLLA) (n = 8), (6) BIO-Cage 2 (PLD-LLA/hydroxylapatite-buffer) (n = 8) and (7) BIO-Cage 3 (PLDLLA/hydroxylapatite particles of different size) (n = 8). Additionally, destructive compression tests of all implants were performed.

RESULTS

In comparison to the intact motion segment all cages showed significantly lower range of motion (ROM) in all test modes (P < 0.01). There was no significant difference in stiffness values and ROM between BIO-Cages and metallic cages. Axial compression stiffness and failure load were significantly highest for metallic BAK-cages (P < 0.05). No significant difference for failure load was observed between BIO-cage 1 and the intact motion segment. However, in comparison to the intact motion segment failure load was significantly lower for BIO-cage 2 and 3 (P < 0.05).

CONCLUSION

The results of this study are encouraging, because the biodegradable cages were able to limit lumbar spine motion similar to the metallic cages. Especially, the biodegradable PLDLLA cage consisting of pure polymer (BIO-Cage 1) showed adequate initial compression strength. However, further in vivo animal experiments are essential prior to the clinical application of biodegradable lumbar interbody fusion cages.

[Transoral atlanto-axial plate fixation in the treatment of a malunited dens fracture and secondary atlanto-axial instability]

INTRODUCTION

A case of a 22-year-old patient with a malunited dens fracture and secondary atlanto-axial instability is presented. The significant narrowing of the spinal canal due to the atlanto-axial instability was associated with anterior myelon compression and neurological deficit.

METHODS

A transoral approach with odontoid resection and anterior atlanto-axial plate fixation was performed. With this technique the atlanto-axial subluxation was reduced and the myelon was decompressed.

RESULTS

The postoperative course was uneventful. The follow-up showed a complete remission of the neurological deficit and a bony fusion of the atlanto-axial joints.

CONCLUSIONS

The presented case illustrates the importance of an accurate initial diagnosis of the degree of instability and the need for short-term follow-up examinations. If atlanto-axial pseudarthrosis or malunion with anterior spinal cord compression occurs, a transoral procedure with odontoid resection and atlanto-axial plate fixation seems to be an excellent salvage procedure.

Impact of carrier solutions on pharmacokinetics of intraperitoneal chemotherapy

PURPOSE

In the treatment of gastrointestinal malignancies with dissemination to peritoneal surfaces the principal advantage of intraperitoneal chemotherapy over intravenous chemotherapy is the high drug concentration achieved locally with low systemic toxicity. This advantage can be optimized by maintaining a large area of contact between the chemotherapy solution and the surfaces within the abdomen and pelvis over a prolonged time period. Using a rat model we compared the pharmacokinetics of two drugs infused intraperitoneally, 5-fluorouracil and gemcitabine, in five different carrier solutions.

METHODS

A total of 120 Sprague Dawley rats were randomized into groups according to the carrier solution and the drug administered. Rats were given a single dose of intraperitoneal 5-fluorouracil (20 mg/kg) or gemcitabine (12.5 mg/kg) in 0.1 ml/g body weight of each carrier solution. The carrier solutions used varied in their tonicity (0.3%, 0.9% or 3% sodium chloride), or were isotonic and varied in molecular weight (0.9% sodium chloride, 4% icodextrin and 6% hetastarch). With the hypotonic, isotonic and hypertonic sodium chloride solutions, only 5-fluorouracil was used. Each group was further randomized according to the intraperitoneal dwell period (1, 3 or 6 h). At the end of the procedure the rats were killed, the peritoneal fluid was withdrawn completely and the blood was sampled using a standardized protocol. The volume of the peritoneal fluid was recorded, and the drug concentrations in the peritoneal fluid and plasma were determined by high-performance liquid chromatography.

RESULTS

Measurements of peritoneal fluid volume showed a more rapid clearance of hypotonic and isotonic sodium chloride solutions from the peritoneal cavity as compared to hypertonic sodium chloride and high molecular weight solutions. When comparing the remaining intraperitoneal volumes at 6 h, the differences were statistically significant for both 5-fluorouracil and gemcitabine when hetastarch (P < 0.0001 and P = 0.0004) and icodextrin (P = 0.002 and 0.008) were compared with isotonic sodium chloride solution. Similarly, there was a significant difference in the volumes recorded at 6 h when hypotonic (P < 0.0001) and isotonic sodium chloride solutions (P = 0.0002) were compared with hypertonic sodium chloride solution. The concentrations of chemotherapy in the different carrier solutions varied little. The total amount of drug in the peritoneal cavity decreased with all solutions and more quickly with 5-fluorouracil than with gemcitabine. There was a significant difference in the total intraperitoneal 5-fluorouracil between hypotonic and isotonic sodium chloride solutions at 1 h (P = 0.0003) and 3 h (P = 0.0043), as well as between the isotonic and hypertonic sodium chloride solutions at 1 h (P = 0.03) and 3 h (P < 0.0001). Similarly, there was a significant difference in the total peritoneal gemcitabine at 6 h between icodextrin and isotonic sodium chloride solution (P = 0.01) and between hetastarch and isotonic sodium chloride solution (P = 0.05). There were no significant differences in plasma 5-fluorouracil and plasma gemcitabine concentrations obtained with the five solutions.

CONCLUSIONS

These findings show that the clearance of 5-fluorouracil and gemcitabine from the peritoneal cavity can be significantly modified by varying the tonicity or the molecular weight of the carrier solution. Peritoneal fluid clearance was slower with hypertonic sodium chloride and high molecular weight solutions and this resulted in a reduced clearance of chemotherapy. By using a high molecular weight carrier solution the exposure of intraperitoneal cancer cells to gemcitabine was prolonged and drug availability at the peritoneal surface was increased. Similarly, by using a hypertonic carrier solution the exposure to 5-fluorouracil was prolonged and drug availability at the peritoneal surface was also increased.