MRI of marked dural sac compression by surgicel in the immediately postoperative period after uncomplicated lumbar laminectomy

Variants of Oxidized Regenerated Cellulose and Their Distinct Effects on Neuronal Tissue

Based on oxidized regenerated cellulose (ORC), several hemostyptic materials, such as Tabotamp^®, Equicel^® and Equitamp^®, have been developed to approach challenging hemostasis in neurosurgery. The present study compares ORC that differ in terms of compositions and properties, regarding their structure, solubility, pH values and effects on neuronal tissue. Cytotoxicity was detected via DNA-binding fluorescence dye in Schwann cells, astrocytes, and neuronal cells. Additionally, organotypic hippocampal slice cultures (OHSC) were analyzed, using propidium iodide, hematoxylin-eosin, and isolectin B₄ staining to investigate the cellular damage, cytoarchitecture, and microglia activation. Whereas Equicel^® led to a neutral pH, Tabotamp^® (pH 2.8) and Equitamp^® (pH 4.8) caused a significant reduction of pH (p < 0.001). Equicel^® and Tabotamp^® increased cytotoxicity significantly in several cell lines (p < 0.01). On OHSC, Tabotamp^® and Equicel^® led to a stronger and deeper damage to the neuronal tissue than Equitamp^® or gauze (p < 0.01). Equicel^® increased strongly the number of microglia cells after 24 h (p < 0.001). Microglia cells were not detectable after Tabotamp^® treatment, presumably due to an artifact caused by strong pH reduction. In summary, our data imply the use of Equicel^®, Tabotamp^® or Equitamp^® for specific applications in distinct clinical settings depending on their localization or tissue properties.

Postoperative Spinal Epidural Hematoma: The Danger Caused by the Misuse of Thrombin-Containing Local Hemostatics

Study Design

Retrospective case-control study.

Purpose

To examine the hypothesis that the misuse of thrombin-containing local hemostatics (TCLH) increases the risk of postoperative spinal epidural hematoma (POSEH).

Overview of Literature

Many studies have focused on hypocoagulability as a risk factor for POSEH. However, there are no prior reports on the increased risk of POSEH in hypercoagulable states.

Methods

Posterior instrumented lumbar spine surgery cases over 2 consecutive years were divided into two groups: a study group (98 patients in whom TCLH was used) and a control group (176 patients in whom TCLH was not used). The excess TCLH matrix that was not associated with blood clot was not removed from the patients in the study group. The senior author decided whether to use TCLH or not. Suction drains were used in all patients. The demographics, coagulation-related factors, and intraoperative factors of the patients in the two groups were analyzed. The development of POSEH was compared between the two groups.

Results

The two groups were homogenous in demographics (age and sex), coagulation-related factors (platelet count, prothrombin time, activated partial thromboplastin time, and platelet function analysis), and surgical factors (total blood loss, operation time, blood loss/10 minutes, number of fusion segments, posterolateral fusion/posterior lumbar interbody fusion, and virgin or revision surgery). POSEH developed more frequently in the patients in the study group than in those in the control group (14/98 patients, 14.3% vs. 3/176 patients, 1.7%, respectively; p=0.001; odds ratio, 17.1).

Conclusions

TCLH causes blood clot not only at the edge of damaged vessels but also at the site of extravascular blood. Excess TCLH matrix not associated with blood clot at the epidural space can enhance POSEH development because early clotted hematomas do not drain through suction drains.

Early Postoperative Magnetic Resonance Imaging in Detecting Radicular Pain After Lumbar Decompression Surgery: Retrospective Study of the Relationship Between Dural Sac Cross-sectional Area and Postoperative Radicular Pain

STUDY DESIGN

A retrospective analysis.

OBJECTIVE

To evaluate the association between early postoperative dural sac cross-sectional area (DCSA) and radicular pain.

SUMMARY OF BACKGROUND DATA

The correlation between postoperative magnetic resonance imaging (MRI) findings and postoperative neurological symptoms after lumbar decompression surgery is controversial.

METHODS

This study included 115 patients who underwent lumbar decompression surgery followed by MRI within 7 days postoperatively. There were 46 patients with early postoperative radicular pain, regardless of whether the pain was mild or similar to that before surgery. The intervertebral level with the smallest DCSA was identified on MRI and compared preoperatively and postoperatively. Risk factors for postoperative radicular pain were determined using univariate and multivariate analyses. Subanalysis according to absence/presence of a residual suction drain also was performed.

RESULTS

Multivariate regression analysis showed that smaller postoperative DCSA was significantly associated with early postoperative radicular pain (per -10 mm; odds ratio, 1.26). The best cutoff value for radicular pain was early postoperative DCSA of 67.7 mm. Even with a cutoff value of <70 mm, sensitivity and specificity are 74.3% and 75.0%, respectively. Early postoperative DCSA was significantly larger before suction drain removal than after (119.7±10.1 vs. 93.9±5.4 mm).

CONCLUSIONS

Smaller DCSA in the early postoperative period was associated with radicular pain after lumbar decompression surgery. The best cutoff value for postoperative radicular pain was 67.7 mm. Absence of a suction drain at the time of early postoperative MRI was related to smaller DCSA.

Spinal subdural hematoma: a rare case of spinal subdural hematoma complicating routine, minimally invasive lumbar discectomy and decompression and relevant literature review

We present a case of apparently uncomplicated lumbar decompression and discectomy with delayed postoperative neurological deterioration secondary to subdural hematoma at the thoracolumbar level of the spinal cord. Previously described subdural hematomas have occurred spontaneously or related to iatrogenic injury. Hitherto, no case of acute postoperative subdural hematoma has been reported in the postoperative setting in the absence of known iatrogenic dural injury. A 76-year-old male with central and lateral recess spinal stenosis underwent apparently uncomplicated bilateral L3-4 and left sided L4-5 decompressive partial laminectomies and discectomy. No incidental dural injury or cerebrospinal fluid leak was detected. On postoperative day two, he developed progressive, profound weakness, sensory changes and urinary retention. Magnetic resonance imaging (MRI) demonstrated a compressive subdural fluid collection extending between T11-L2, which was confirmed to be xanthochromic and under pressure superficial to an undisturbed arachnoid at emergent surgical exploration and evacuation. The mechanism of this complication is unknown. The patient went on to a complete recovery following surgical evacuation of the fluid via durotomy. While this is a very rare event, it reminds that a high index of suspicion is required with a low threshold for urgent imaging and intervention in the postoperative period upon development of unexpected, progressive and/or profound neurological findings regardless of intraoperative course.

Can We Prevent a Postoperative Spinal Epidural Hematoma by Using Larger Diameter Suction Drains?

Background

Epidural hematoma is a rare but serious complication. According to previous studies, it is not prevented by suction drains. This study evaluated the following alternative hypothesis: the larger the diameter of a suction drain, the less the remaining epidural hematoma after spinal surgery.

Methods

This was a randomized prospective study. Patients who underwent posterior lumbar decompression and instrumented fusion were divided into two groups: the large drain (LD, 2.8-mm-diameter tube) and small drain (SD, 1.6-mm-diameter tube) groups according to the diameter of the suction drains. All patients were consecutive and allocated alternately according to the date of operations. Suction drains were removed on day 3 and magnetic resonance imaging was performed on day 7 postoperatively. The size of remaining hematomas was measured by the degree of thecal sac compression in cross section using the following 4-point numeric scale: G1, less than one quarter; G2, between one quarter and half; G3, more than half; and G4, more than subtotal obstruction.

Results

There were 39 patients with LDs and 38 with SDs. They did not differ significantly in terms of sex, number of fusion segments, revision or not, antiplatelet medication, intraoperative injection of tranexamic acid. However, patient age differed significantly between the two groups (LD, 63.3 years and < SD, 68.6 years; p = 0.007). The two groups did not differ significantly in terms of prothrombin time, activated partial thromboplastin time, platelet number, blood loss, or operation duration. However, platelet function analysis exhibited a significant difference (LD, 164.7 seconds and < SD, 222.3 seconds; p = 0.002). The two blinded readers showed high consistency (Kappa value = 0.740; p = 0.000). The results of reader 1 were as follows: LD and SD had 21 and 21 cases of G1, 9 and 11 cases of G2, 6 and 6 cases of G3, and 3 and 0 cases of G4, respectively. The results of reader 2 were as follows: LD and SD had 22 and 23 cases of G1, 7 and 9 cases of G2, 7 and 6 cases of G3, and 3 and 0 cases of G4, respectively. There was no difference between the two groups (reader 1, p = 0.636; reader 2, p = 0.466).

Conclusions

The alternative hypothesis was rejected. Therefore, postoperative spinal epidural hematoma would not be prevented by LD.

Fatal intraoperative cardiac arrest after application of surgifoam into a bleeding iliac screw defect

STUDY DESIGN

Case report.

OBJECTIVE

To describe the presentation, management, and autopsy findings in a case of a fatal intraoperative cardiac arrest after application of an absorbable hemostatic agent into a bleeding iliac bone screw defect.

SUMMARY OF BACKGROUND DATA

To the authors' knowledge, this represents the first reported complication of intraoperative death associated with Surgifoam (Ethicon) thromboembolization to the heart and lung microcirculation after its application into a bleeding bone defect.

METHODS

A 56-year-old male was undergoing revision fusion surgery for pseudarthrosis after multilevel thoracolumbosacral fusion with pelvic fixation for degenerative scoliosis. Intraoperatively, upon removal of the right iliac screw, heavy venous bleeding was encountered, which was stopped after application of 10 mL of Surgifoam into the screw defect. Approximately 5 minutes later, the patient's end tidal CO2 dropped, and his pulse was lost. Epinephrine was administered and the patient was immediately turned to supine position and cardiopulmonary resuscitation initiated. Cardiopulmonary resuscitation was performed unsuccessfully for 30 minutes at the end of which the patient was pronounced dead.

RESULTS

Autopsy findings revealed angulated particles of hemostatic agent with entrapped red blood cells partially to completely occluding small-to-medium-sized vessels of the heart and lungs. The cause of death was pulmonary and cardiac embolization of foreign material from the surgical screw defect to the vessels of the heart and lungs, significantly compromising respiration and blood flow causing sudden death.

CONCLUSION

Although Surgifoam is an excellent hemostatic agent for use in spinal surgery, it must be used with extreme caution in the setting of heavily bleeding bone defects after pedicle cannulation or removal of instrumentation. In cases when brisk venous bleeding is encountered, signifying potential compromise of an emissary vein, use of other hemostatic agents such as bone wax may be a safer option.

LEVEL OF EVIDENCE

N/A.

Evaluation of resorption and biocompatibility of collagen hemostats in the spinal epidural space

BACKGROUND CONTEXT

Collagen hemostats have different characteristics depending on their properties and configuration. In vivo serial evaluation of local reactions because of placement of hemostats in the epidural space has not been reported.

PURPOSE

This study compared the resorption and biocompatibility of two types of collagen hemostats placed in the epidural space.

STUDY DESIGN

This in vivo study used experimental animals to evaluate collagen hemostats that were placed in the epidural space.

METHODS

A ligamentum flavum resection model was created in Japanese white rabbits (n=65). A microfibrillar collagen hemostat (MCH group, n=5), cotton-type collagen hemostat (CCH group, n=5) that was chemically cross-linked, or no hemostat (control group, n=4) was placed in the spinal epidural space. For histologic evaluation, each group was euthanized 1, 2, 4, and 8 weeks postoperatively (PO), and hematoxylin-eosin and immunohistochemical (IHC) staining for inflammatory cytokines (tumor necrosis factor [TNF]-α, interleukin [IL]-6), cyclooxygenase (COX)-2, and macrophages (CD68) was performed. To evaluate exudate accumulation and the degree of inflammation in the epidural space, magnetic resonance imaging at 7.04 T was serially performed in each group (n=3) under anesthesia and sedation.

RESULTS

The collagen hemostats in both groups were reabsorbed at 4 weeks PO. In the MCH group, there was inflammatory cell infiltration and granuloma formation around the hemostat, TNF-α-positive cells were seen up to 1 week, and IL-6-, COX-2-, and CD68-positive cells were seen at all evaluation times. In the CCH group, no inflammatory cell infiltration around the hemostat was observed, and IHC staining showed no positive cells at 4 weeks PO and later. T2*-weighted MR images showed significantly higher mean signal intensity of the epidural space in the MCH group than in the CCH group but only at 1 week PO (p<.05).

CONCLUSIONS

Resorption of both hemostats was similar. In the MCH group, there was intense tissue inflammation around the hemostatic material, and MR images showed high signal intensity because of exudate accumulation in the epidural space. This indicated a strong foreign-body reaction to the MCH, thus demonstrating a difference in biocompatibility with the CCH.

Acute respiratory failure from Surgifoam expansion after anterior cervical surgery

A 65-year-old woman underwent an uneventful C3–4 anterior cervical discectomy and fusion for a large, symptomatic disc herniation. On postoperative Day 1 the patient suffered a sudden, acute respiratory compromise. Emergency fiberoptic intubation revealed significant anterior neck swelling with concern for physical obstruction of the airway. Computed tomography of the neck did not demonstrate an expanding hematoma. The patient was managed with surgical wound exploration and washout. Examination of the anterior neck after incision of the prior surgical site revealed a large volume of Surgifoam under high pressure, which was greater than the amount used during the initial surgery. Thorough washout of the surgical site did not reveal any swelling of the prevertebral soft tissues or hematoma, and the Hemovac drain did not appear to be occluded. The patient was extubated on the 2nd postoperative day and is symptom free 12 months after surgery. To the authors' knowledge, this report represents the first reported complication of acute respiratory failure from Surgifoam overexpansion after anterior cervical surgery.

Routine postoperative imaging early after lumbar decompression surgery: a prospective evaluation

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To determine the value of routine postoperative magnetic resonance imaging early after lumbar decompression in patients with nonspecific symptoms.

SUMMARY OF BACKGROUND DATA

Imaging after lumbar surgery may be performed more readily in patients even with nonspecific symptoms and without neurological deficit.

METHODS

Patients undergoing elective lumbar decompression surgery completed standardized questionnaires, were assessed neurologically on admission, and underwent magnetic resonance scanning within 72 hours after surgery. Residual stenosis was graded as absent or mild (outcome A) or moderate to severe (outcome B). Surgical technique and intraoperative complications and postoperative neurological status were recorded.

RESULTS

We recruited 28 consecutive patients who reported significant improvement in preoperative symptoms. In two-thirds of all patients, postoperative images showed at least one segment with moderate or severe residual stenosis (outcome B). Radiological outcome did not correlate with postoperative pain. Patient satisfaction index was comparable in groups A and B. The cross section of the spinal canal was significantly wider with a drain in situ. This did not, however, translate into a difference in overall visual analogue scale score or wound discomfort. Patients tended to report more back and leg pain with drains and were less satisfied with the result of the operation.

CONCLUSION

Early postoperative magnetic resonance scans in patients with nonspecific symptoms frequently show radiologically relevant stenosis, which is associated with neither outcome nor patient satisfaction. Drain placement is associated with less radiological narrowing but with lower patient satisfaction. Imaging without clinical correlate may yield nondiscriminatory information likely to unsettle and puzzle both patients and health care providers.

LEVEL OF EVIDENCE

3.

Early postoperative MRI in detecting hematoma and dural compression after lumbar spinal decompression: prospective study of asymptomatic patients in comparison to patients requiring surgical revision

Early postoperative MRI after spinal surgery is difficult to interpret because of confounding postoperative mass effects and frequent occurrence of epidural hematomas. Purpose of this prospective study is to evaluate prevalence, extent and significance of hematoma in the first postoperative week in asymptomatic patients after decompression for lumbar stenosis and to determine the degree of clinically significant dura compression by comparing with the patients with postoperative symptoms. MRI was performed in 30 asymptomatic patients (47 levels) in the first week after lumbar spine decompression for degenerative stenosis. Eleven patients requiring surgical revision (16 levels) for symptomatic early postoperative hematoma were used for comparison. In both groups the cross-sectional area of the maximum dural compression (bony stenosis and dural sac expansion) was measured preoperatively and postoperatively by an experienced radiologist. Epidural hematoma was seen in 42.5% in asymptomatic patients (20/47 levels). The median area of postoperative hematoma at the operated level was 176 mm(2) in asymptomatic patients and 365 mm(2) in symptomatic patients. The median cross-sectional area of the dural sac at the operated level was 128.5 and 0 mm(2) in asymptomatic and symptomatic patients, respectively, at the site of maximal compression. In the symptomatic group 75% of the patients had a maximal postoperative dural sac area of 58.5 mm(2) or less, whereas in the asymptomatic group 75% of patients with epidural hematoma had an area of 75 mm(2) or more. The size of hematoma and the degree of dural sac compression were significantly larger in patients with symptoms needing surgical revision. Dural sac area of less than 75 mm(2) in early postoperative MRI was found to be the threshold for clinical significance.

Radiculopathy after lumbar discectomy due to intraspinal retained Surgicel: clinical and magnetic resonance imaging evaluation

BACKGROUND CONTEXT

Lumbar radiculopathy after lumbar spine surgery is an alerting sign usually caused by either a recurrent disc herniation or epidural hematoma. However, pressure on a spinal nerve root may also be exerted by a retained piece of Surgicel used to achieve hemostasis during lumbar spine surgical procedures.

PURPOSE

To describe a case of lumbar radiculopathy that was caused by a piece of Surgicel left in the spinal canal after operation for lumbar disc herniation.

STUDY SETTING

A case report of a retained piece of Surgicel being the cause of S1 radiculopathy.

METHODS

Patient interview, medical records, imaging studies, and literature review.

RESULTS

A 29-year-old man developed acute left S1 radiculopathy after a successful hemilaminectomy and discectomy operation for a L5-S1 disc herniation. In the magnetic resonance imaging studies that were performed, a postoperative hematoma could not be excluded and a reoperation revealed compression from Surgicel that was used for hemostasis. The patient was free of symptoms after reoperation.

CONCLUSIONS

This case depicts the difficulty in distinguishing-by means of magnetic resonance imaging-nerve root compression caused by a postoperative hematoma and a recurrent disc herniation, from that caused by a retained Surgicel. Therefore, hemostatic agents should be meticulously used in spine surgery.

Clinical benefits and risk analysis of topical hemostats: a review

A variety of local hemostats including absorbable gelatin sponge, collagen hemostat, and oxidized cellulose are commercially available. Local hemostats are applied when cautery, ligature, or other conventional hemostatic method is impractical. Proper handling is essential to control bleeding and only the required amount should be used, even though the hemostat is expected to dissolve promptly. A dry local hemostat absorbs body fluid of several times its own weight and expands postoperatively. Therefore, when an absorbable hemostatic agent is retained on or near bony or neural spaces, the minimum amount should be left after hemostasis is achieved. Documentation is important with regard to the hemostat used, including the name of the agent, site, and amount. This information is used as a reference in the interpretation of postoperative diagnostic images, since retained hemostat may sometimes mimic an abscess or recurrent tumor. The antigenicity of collagen is known to be low because of homology. When the safety of collagen was evaluated, the incidence of positive reactions was reported as 3.0%, and collagen may cause allergic reactions. Minimum inflammation without strong foreign body reactions or blockade of healing is desirable after the use of local hemostats. Strong foreign body reactions, chronic inflammation, and infections can cause granuloma formation after local hemostat use. By using local hemostats, it is possible to improve the condition of the patient, reduce complications, and lower direct and indirect costs.

Postoperative paraplegia secondary to the use of oxidized cellulose (Surgicel)

Iatrogenic paraplegia after thoracic surgery is a devastating complication. In this report, the authors present a case of paraplegia in a toddler after the resection of a mediastinal neuroblastoma. In this case, the paraplegia was caused by spinal cord compression after migration of oxidized cellulose into the spinal canal.

An overview of blood-sparing techniques used in spine surgery during the perioperative period

The problems linked to blood loss and blood-sparing techniques in spine surgery have been less studied than in other fields of orthopedics, such as joint-replacement procedures. Decreasing bleeding is not only important for keeping the patient's hemodynamic equilibrium but also for allowing a better view of the surgical field. In spine surgery the latter aspect is especially important because of the vicinity of major and highly fragile neurologic structures. The techniques and agents used for hemostasis and blood sparing in spinal procedures are mostly similar to those used elsewhere in surgery. Their use is modulated by the specific aspects of spinal approach and its relation to the contents of the spinal canal. Blood-sparing techniques can be divided into two categories based on their goals: either they are aimed at decreasing the bleeding itself, or they are aimed at decreasing the need for homologous transfusion. Various hemodynamic techniques, as well as systemic and local drugs and agents, can be used separately or in combination, and their use in the field of spine surgery is reported. The level of evidence for the efficacy of many of those methods in surgery as a whole is limited, and there is a lack of evidence for most of them in spine surgery. However, several blood-saving procedures and drugs, as well as promising new agents, appear to be efficient, although their efficacy has yet to be assessed by proper randomized controlled trials.