Abstract

Background: Patients with postoperative spinal epidural hematomas (pSEH) typically require emergency treatment to avoid paralysis; these hematomas should not be ignored. pSEH patients need to undergo immediate MR studies to document the location/extent of their hematomas, and emergent surgical decompression with/ without fusion if warranted.

Methods: The frequencies of symptomatic pSEH ranged in various series from 0.1%-4.46%. Major predisposing factors included; perioperative/postoperative coagulation abnormalities/disorders, multilevel spine surgeries, previous spine surgery, and intraoperative cerebrospinal fluid (CSF) leaks. For surgery at all spinal levels, one study observed pSEH developed within an average of 2.7 postoperative hours. Another series found 100% of cervical/thoracic, and 50% of lumbar pSEH were symptomatic within 24 postoperative hrs., while a third series noted a 24-48 postoperative window for pSEH to develop.

Results: Early recognition of postoperative symptoms/signs of pSEH, warrant immediate MR examinations to diagnose the local/extent of hemorrhages. Subsequent emergent spinal decompressions/fusions are critical to limit/avert permanent postoperative neurological deficits. Additionally, patients undergoing open or minimally invasive spinal procedures where pSEH are suspected, warrant immediate postoperative MR studies.

Conclusion: Patients undergoing spinal surgery at any level typically become symptomatic from pSEH within 2.7 to 24 postoperative hours. Early recognition of new neurological deficits, immediate MR studies, and emergent surgery (i.e., if indicated) should limit/minimize postoperative neurological sequelae. Thus, pSEH should be treated, not ignored.

Keywords: Emergency, Diagnosis, Surgery, Postoperative spinal epidiural hematomas (pSEH), Not ignored, Avoid delays, Paralysis, Early diagnosis, Early surgery

INTRODUCTION

The incidence of symptomatic postoperative spinal epidural hematomas (pSEH) occurring at varying spinal levels ranged in 7 series from 0.1% to 1%,[ 1 , 2 , 4 , 8 , 9 , 15 , 16 ] in 5 studies it ranged from < 1% up to 2.9%,[ 11 , 12 , 15 , 17 , 18 ] and in 3 papers from 3%-4.46% [ Tables 1 and 2 ].[ 2 , 6 , 17 ] Major predisposing factors for pSEH included; perioperative/postoperative coagulation disorders, multilevel spinal surgery, prior spine surgery, and intraoperative cerebrospinal fluid leaks (CSF) [ Tables 1 and 3 ].[ 1 - 18 ] The times to onset of symptomatic postoperative pSEH following all-level spine surgery ranged from an average of 2.7 postoperative hours,[ 1 ] to less than 24,[ 2 ] to between 24-48 postoperative hrs.[ 5 ] [ Tables 1 - 4 ].[ 1 , 2 , 5 ] Notably, minimally invasive surgery increased the risk of pSEH 5-fold vs. open procedures.[ 4 ] The most critical factors to limit/avert permanent neurological sequelae of pSEH included; early recognition of new postoperative neurological deficits, obtaining immediate magnetic resonance imaging (MR) studies, and performing emergency spine surgery where indicated [ Tables 1 - 4 ].[ 1 - 18 ]

Table 1:

Incidence and treatment of postoperative spinal epidural hematomas (pSEH).

Table 2:

Incidence of postoperative spinal epidural hematomas (PSEH).

Table 3:

Risk factors predisposing to postoperative spinal epidural hematomas (pSEH).

Table 4:

Spinal Levels of pSEH.

Incidence of pSEH

The incidence of symptomatic postoperative spinal epidural hematomas (pSEH) involving all spinal levels ranged in 7 studies from 0.1% to 1%,[ 1 , 2 , 4 , 8 , 9 , 15 , 16 ] in 5 series from <1% to 2.9%,[ 11 , 12 , 15 , 17 , 18 ] and in 3 series between 3%-4.46% (i.e., the 1 of 10 patients with a 10% incidence of pSEH was considered an outlier)[ 2 , 6 , 17 ] [ Tables 1 and 2 ].[ 1 - 18 ]

Multiple Risk Factors Associated with pSEH

The most common risk factors predisposing patients to pSEH included; perioperative/postoperative coagulopathy,[ 5 , 8 , 9 , 11 , 12 , 16 , 18 ] multilevel surgery,[ 1 , 5 , 8 , 11 , 12 ] prior spine surgery,[ 1 , 18 ] intraoperative CSF leaks,[ 18 ] advanced age,[ 5 , 11 ] and minimally invasive surgery (i.e. 5-fold increase in pSEH) [ Tables 1 and 3 ].[ 1 - 18 ] Other studies mentioned less frequently encountered risk factors [ Table 3 ]. In Kou et al. (2002) series involving 12 (2.9%) pSEH of 416 patients undergoing lumbar laminectomy/ decompressions, the 2 major risk factors included multilevel surgery, and perioperative coagulopathies.[ 12 ] Amiri et al. (2013) found a 0.22% incidence of pSEH out of 4568 all-level spinal procedures with alcohol abuse (i.e. >10 units/week), prior spine surgery, and multilevel surgery predisposing to pSEH.[ 1 ] For Guodong et al. (2014) series of 12 (0.5%) cervical pSEH out of 2338 patients undergoing cervical surgery, risk factors included hypertension in 2/3 of patients, and multilevel surgery; notably, none had coagulopathies.[ 8 ] Following 310 biportal endoscopic procedures, immediate postoperative MR scans in Kim et al. (2019) series documented a 1.9% incidence of symptomatic pSEH; here major risk factors included age over 70, more extensive surgery/more bone work (laminectomy/interbody fusion), and anticoagulation therapy.[ 11 ] Eguchi et al. (2019) observed a 3.7% rate of pSEH out of 133 patients undergoing thoracolumbar posterior spinous process splitting procedures/fusions (PSPS), and risk factors here included; surgery at/above the L2/3 level, and reduced postoperative drainage.[ 6 ] Risk factors in Hohenberger et al. (2020) 42 (0.69%) of 6024 patients undergoing all-level spine surgery included preoperative anticoagulation/ coagulopathy, and smoking.[ 9 ] For Wang et al. (2022) 24 (1.49%) pSEH of 1612 patients undergoing thoracic surgery, major predisposing risk factors included an intraoperative cerebrospinal fluid (CSF) leak, a kyphotic angle of greater than 8.77 degrees, a cross-section/ axial occupancy ratio of > 49.58%, coagulopathy, and a history of prior spine surgery.[ 18 ] For 37 (0.39%) pSEH of 9307 patients undergoing thoracolumbar surgery, Saitta et al. (2022) major risk factors included hypertension and coagulopathies; they also recommended careful monitoring of drain output for those on antiplatelet regimens.[ 16 ] Chen et al. (2022) meta-analysis of 40 studies (i.e., noting 0.52% frequency of pSEH for all-level surgery) concluded that pSEH were not increased by perioperative anticoagulation; rather, minimally invasive (MI) spinal procedures increased the risk of pSEH 5-fold (1.94%) vs. open surgery (i.e., 0.425%).[ 4 ] Djurasovic et al. (2022) quoted a range of 0.1-0.69% in the literature for pSEH occurring in all spinal proceudres; their identiifed risk factors included older age, anticoagulation, and multilevel laminectomy.[ 5 ]

Controversy Regarding Correlation of Perioperative/Postoperative Coagulation Disorders with pSEH

Perioperative/Postoperative Coagulation Disorders Increased Risk of pSEH

In 6 spinal series, authors determined that preoperative/perioperative coagulation disorders/ coagulation abnormalities increased the risk of pSEH [ Tables 1 and 3 ].[ 5 , 9 , 11 , 12 , 16 , 18 ] Kou et al. (2002) found that coagulation abnormalities increased the risk of pSEH following lumbar surgery (i.e., 12 (2.9%) pSEH of 416 patients)).[ 12 ] Kim et al. (2019) determined that for the 1.9% of patients developing pSEH out of a series of 310 patients undergoing biportal endoscopic spine surgery, anticoagulation was a major risk factor.[ 11 ] In Hohenberger et al. (2020) (0.69% or 42 of 6024 patients undergoing all level surgeyr), in Wang et al. (2022) (1.49% or 24 pSEH of 1612 thoracic procedures), in Saitta et al. (2022) (0.39% or 117 pSEH of 9307 having thoracolumbar surgery), and Djurasovic et al. (2022) (0.1-0.6% all level surgery), the multiple authors considered anticoagulation to be a significant risk factor for pSEH.[ 5 , 9 , 16 , 18 ]

Perioperative Chemoprophylaxis for Deep Venous Thrombosis (DVT)/Pulmonary Embolism (PE) “May” Increase the Risk for pSEH

Two studies determined that chemoprophylaxis for Deep Venous Thrombosis (DVT)/Pulmonary Embolism (PE) “may” increase the risk for pSEH.[ 3 , 7 ] Butler et al. (2022) specifically acknowledged that DVT/PE prophylaxis “may” increase the risk of lumbar pSEH.[ 3 ] Glotzbecker et al. (2010) evaluated 16 articles dealing with all-level spine surgery, and found the frequency of pSEH was 0-0.7% with chemoprophylaxis vs. a nearly comparable 0-1% without such treatment.[ 7 ] They concluded that; “...evidence suggests that use of therapeutic doses of heparin in postop spinal patients who sustain a PE may have a higher incidence of bleeding complications”.

Perioperative/Postoperative Coagulation Disorders/ Chemoprophylaxis Did Not Increase the Risk of pSEH

Two studies documented no increased risk of pSEH in patients with perioperative and/or postoperative coagulation abnormalities/disorders/chemoprophylaxis [ Tables 1 - 4 ].[ 4 , 8 ] Guodong et al. (2014) determined that coagulation disorders did not contribute to the frequency of cervical pSEH (i.e., 0.5% or 12 pSEH of 2338 patients).[ 8 ] In a meta-analysis of 40 studies, Chen et al. (2022) similarly found a 0.52% incidence of pSEH after all-level spine surgery; they, too concluded that coagulation disorders did not contribute to the frequency of pSEH.[ 4 ]

Minimally Invasive Surgery Increases Risk of pSEH 5-Fold

In Chen et al. (2022) meta-analysis of 40 studies, showing an overall 0.52% frequency of pSEH for all-level spinal procedures, they very specifically noted that minimally invasive (MI) operations increased the risk of pSEH 5-fold (1.94%) vs. open surgery (i.e. a lesser 0.425%) [ Tables 1 - 4 ].[ 4 ]

Placement of Thoracic Spinal Cord Stimulators (SCS) Increased Risk of pSEH 3-Fold

Moufarrij et al. (2016) found a 3-fold higher rate of pSEH for 4 (2.6%) of 154 patients undergoing SCS (i.e., placement of thoracic paddle leads for thoracic spinal cord stimulators through laminectomies); for the 119 control patients undergoing thoracic laminectomies without SCS placement, the frequency was a much lower 0.84% (i.e., 1 case of pSEH) [Tables 1and 4].[ 15 ]

Controversy Regarding Utility of Drains in Spinal Surgery to Avoid pSEH

Use of Drains to Monitor Output and Predict Onset of pSEH

Two studies advocated monitoring postoperative drainage following spine surgery to anticipate an increased risk for pSEH [ Tables 1 and 3 ].[ 6 , 16 ] For Eguchi et al. 3.7% of 133 patients who developed pSEH following posterior thoracolumbar surgery, reduced postoperative drainage potentially signaled the onset/presence of a pSEH.[ 6 ] Further, when Saitta et al. (2022) diagnosed 37 (0.39%) of 9307 patients with symptomatic pSEH following thoracolumbar surgery, monitoring significant changes in postoperative drainage, especially in those on antiplatelet therapy, helped identify those at risk for pSEH.[ 16 ]

Drains In Spine Surgery Did Not Reduce the Incidence of pSEH

Three series concluded that placing drains during spine surgery did not reduce the frequency of pSEH [ Tables 1 and 3 ].[ 1 , 3 , 5 ] Kou et al. (2002) found that drains did not influence the 2.9% incidence (i.e., 12 pSEH of 416 patients) of pSEH occurring following lumbar laminectomies.[ 12 ] Looking at the incidence of pSEH following lumbar surgery, Butler et al. (2022) found no support regarding the efficacy of subfascial drains in reducing pSEH.[ 3 ] Further, when Djurasovic et al. (2022) evaluated the frequency of pSEH following all-level spine surgery, drains did not effectively decrease the incidence of pSEH.[ 5 ]

Symptoms and Signs of pSEH

Several common symptoms and signs (i.e., acute increased postoperative pain, radiculopathy, weakness (i.e. including paraplegia), and sphincter dysfunction) signaled the presence/onset of pSEH following spinal surgery [ Table 1 ].[ 3 , 5 , 10 ] In Kebaish et al. (2004) series, the multiple etiologies of postoperative spinal hematomas included; trauma, anticoagulation, vascular lesions, and postoperative epidural hemorrhages (i.e., quoted the incidence of pSEH in the literature between 0.1 to 3%).[ 10 ] For Butler et al. (2022) patients undergoing lumbar surgery, symptoms/signs of postoperative cauda equina syndromes included acute worsening or excruciating low back pain, and weakness; patients typically warranted immediate postoperative MR scans, and emergent decompressive surgery with/without fusions.[ 3 ] Symptoms/signs for those with pSEH in Djurasovic et al. (2022) all-level spine series included; postoperative back/leg pain, new radicular deficits, significant weakness, and/or compromise/loss of sphincter function.[ 5 ]

Acute pSEH can be Diagnosed on Immediate Postoperative MR Scans Despite Metal Artifact

MR scans are the “gold standard” for diagnosing immediate pSEH despite metallic artifact from instrumentation [ Table 1 ].[ 11 , 17 ] In 2013, Shin et al. (2017), immediate postoperative MR scans in 10 patients undergoing thoracic posterior spinal fusions yielded one patient (10%) with a pSEH; this was readily identified by the clear loss of cerebrospinal fluid around the cord, and was readily diagnosed despite artifact from instrumentation.[ 17 ] These same authors also similarly diagnosed 3 (1.15%) of 260 pSEH from a comparable prior series of patients undergoing thoracic instrumented fusions. Kim et al. (2019), following biportal endoscopic thoracolumbar spine surgery, also readily diagnosed pSEH on immediate postoperative MR scans in 1.9% symptomatic patients (i.e, out of a total of 310 patients); however, they also found that an additional 23.6% (94 patients) of patients had asymptomatic pSEH.[ 11 ]

Gelfoam and/or Surgiflo If not Removed During Spinal Decompressions/Laminectomy May Swell/ Contribute to pSEH

Package inserts for both Gelfoam (i.e., Pharmacia and Upjohn Company 7000 Portage Road, Kalamazoo, Michigan 49001 USA), and Surgiflow Hemostatic Matrix (i.e. Ethicon, Johnson and Johnson 507 Mount Wellington Hwy, Penrose, New Jersey 1060, NZ) warn that these products should be removed if applied during spinal decompressions/laminectomies due to marked swelling (i.e., easily up to 20%). Although significant pSEH due to Gelfoam or Surgiflo can be readily diagnosed based on postoperative MR studies, spinal surgeons need to order these scans and perform definitive surgery in a timely fashion so that these products can be removed.

Gelfoam

The package insert for Gelfoam states; “...it (Gelfoam) should be removed after use in laminectomy procedures and from foramina in bone, once hemostasis is achieved. This is because GELFOAM may swell to its original size on absorbing fluids and produce nerve damage by pressure within confined bony spaces.” They further noted; “When GELFOAM was used in laminectomy operations, multiple neurologic events were reported, including but not limited to cauda equina syndrome, spinal stenosis, meningitis, arachnoiditis, headaches, paresthesias, pain, bladder and bowel dysfunction, and impotence”.

Surgiflo

The warnings for Surgiflo are simlar to those for Gelfoam; “SURGIFLO® should be removed from the site of application when used in, around, or in proximity to foramina in bone...”. “That is; “...because it may swell resulting in nerve damage”. Notably; “Safe and effective use in neurosurgery has not been proven...” Also; “SURGIFLO® may swell up to 20% upon contact with additional fluid...”, and; “...should be removed if possible once hemostasis has been achieved because of the possibility of dislodgment of the device or compression of other nearby anatomic structures.”

MR-Documentation of Spinal Levels of pSEH

MR studies documented that most pSEH occurred in the thoracic spine, followed by the thoracolumbar spine, and cervical spine [ Tables 1, 2, 4 ].[ 1 , 2 , 4 , 6 , 8 , 9 , 11 , 12 , 15 - 18 ] Four studies focused on the 0.22% - 0.69% frequencies of pSEH that followed spine surgery performed at all levels.[ 1 , 2 , 4 , 9 ] Four other series cited 0.21% - 0.54% frequencies of pSEH after cervical surgery that included; 0.21% for Anterior Diskectomy/Fusion (ACDF) and 0.44% for C-LOP (Cervical Laminoplasty).[ 2 ] [ Table 4 ].[ 2 , 4 , 8 , 9 ] Six thoracic series (i.e., including thoracic laminectomies, posterior decompressions/ fusions, and one spinal cord stimulator) cited frequencies of pSEH ranging from 0.12% to 4.46% (i.e., one study was an outlier and cited a 10% rate (i.e., just for 1 of 10 patients)). [ 2 , 4 , 9 , 15 , 17 , 18 ] Three thoracolumbar studies (i.e., involving largely instrumented fusions) cited frequencies of pSEH ranging from 1.9%-3.7%.[ 6 , 11 , 16 ] For 4 lumbar series, the pSEH rate ranged from 0.5% to 2.9%.[ 2 , 4 , 9 , 12 ] Notably, for Aono et al. patients undergoing lumbar procedures, there were no pSEH for those undergoing diskecotmy; however, there was a 0.5% incidence of pSEH following lumbar laminectomy, and an even higher 0.67% frequency of pSEH after posterior lumbar interbody fusions (PLIF).[ 2 ]

Timing to Onset of Symptoms from pSEH Following All-Level, Cervical, Thoracic, and Lumbar Surgery

Time to Onset of Postoperative Symptoms for pSEH After All-Level Spine Surgery

Four studies defined the times to onset of pSEH as ranging from 2.7 hrs., to < 24 hrs, to 24-48 hrs. after all-level spine surgery.[ 1 , 2 , 5 ] Aono et al. (2011) found that (i.e., in 26 (0.41%) pSEH of 6356 patients undergoing spinal surgery at all levels) 100% of patients undergoing cervicothoracic surgery were symptomatic from pSEH within < 24 postoperative hrs. vs. a lesser 50% rate for those undergoing lumbar procedures [ Tables 1 and 4 ].[ 2 ] In Amiri et al. (2013), the average time to the onset of postoperative symptomatic pSEH was just 2.7 postoperative hrs. (i.e., in 100 (0.22%) of 4568 all-level spine operations); therefore, minimal 4-hour postoperative observation windows were critical for patients undergoing ambulatory spine surgery.[ 1 ] Subsequently, in 2022, Djurasovic et al. observed that patients with pSEH typically presented within 24-48 postoperative hours (i.e., incidence 0.1%-0.69% for those undergoing all-level spine surgery).[ 5 ]

Time to Onset of Postoperative Symptoms for Cervical pSEH

For patients undergoing cervical surgery, pSEH were typically symptomatic within < 24 postoperative hours.[ 2 , 8 ] Aono et al. (2011) found pSEH in 0.44% patients following cervical laminoplasties, and 0.21% after cervical ACDF; all patients were typically severely symptomatic in less than 24 postoperative hrs.[ 2 ] Of interest, out of the 2338 cervical operations in Guodong et al. (2014) series, the 12 (0.5%) patients diagnosed with cervical pSEH underwent surgical removed within 2 postoperative hours and, therefore, did well.[ 8 ]

Time to Onset of Postoperative Symptoms for Thoracic/ Thoracolumbar pSEH

The following 3 series focused on the incidence of pSEH for patients undergoing thoracic/thoracolumbar surgery; patients became symptomatic from postoperative pSEH within 3 postoperative hrs. (i.e., 2 case reports), or within 24 hrs. postoperatively [ Tables 1 and 4 ].[ 2 , 13 , 14 ] In Aono et al. (2011) 5 (4.46%) of 112 patients undergoing thoracic laminectomies developed symptomatic pSEH within 24 postoperative hrs.[ 2 ] Martin et al. (2010) 57-year-old female undergoing a T3-sacrum scoliosis procedure was paraplegic from a pSEH within 3 postoperative hours.[ 13 ] Minato et al. (2016) 42-year-old male with a CT-documented T12 Fracture/Dislocation (Type B) who underwent a posterior thoracolumbar fusion without decompression 4 days later, was also symptomatic within 3 postoperative hours from a pSEH (i.e., he developed severe pain and weakness); he also underwent an emergent secondary decompression.[ 14 ]

Time to Onset of Postoperative Symptoms for Lumbar pSEH

In Aono et al. (2011) series. 0.5% of patients undergoing lumbar laminectomies and 0.67% of those having PLIF became symptomatic from pSEH within 24 postoperative hrs. [ Tables 1 and 4 ].[ 2 ]

Early Diagnosis and Emergent Surgery Yielded the Best Outcomes for Patients with pSEH

This perspective emphasizes that early diagnosis and emergent surgery for patients with pSEH yielded the best neurological outcomes [ Tables 1 - 4 ].[ 1 - 3 , 5 , 8 - 10 , 13 ] Kebaish et al. (2004) confirmed that patients with clinical evidence of pSEH should undergo immediate postoperative MR scans to diagnose/confirm their location, and this should be followed by emergent surgical decompressions; “Prognosis depends on the rate of development of symptoms, interval to surgery, level of spinal involvement, and degree of neurological deficit”.[ 10 ] Martin et al. (2010), also noted that early diagnosis of pSEH was critical and stated; “A neurological examination should always be conducted in the operating room immediately after surgery...”[ 13 ] Aono (2011) also noted that; “The shorter the period to evacuation, the better were the results of neurological recovery”.[ 2 ] Amiri et al. (2013) found the best outcomes occurred for surgery performed within 1 ] Alternatively, those operated more than 6 hrs. after the onset of symptoms, had poorer outcomes; they just improved 1 Frankel Grade.[ 1 ] They concluded; “This study suggests that earlier surgical intervention may result in greater neurological recovery”[ 1 ] In Guodong et al. (2014) series, involvling 12 (0.5%) pSEH of 2338 cervical operations, surgery was performed within 2 hours of diagnosing pSEH, leading them to also conclude; “Early diagnosis and evacuation of the hematoma can result in resolution of the neurological deficit.”[ 8 ] Hohenberger et al. (2020) also observed for symptomatic pSEH; “Functional outcome was related to the duration between hematoma evacuation and the clinical presentation of symptomatic pSEH”.[ 9 ] They also emphasized: “Delayed evacuation may result in severe neurological impairment.”[ 9 ] Djurasovic et al. (2022) similarly recommended; “...surgical evacuation should be carried out as quickly as possible”, and; “The prognosis for neurologic improvement after evacuation depends on the time delays and the degree of neurologic impairment before evacuation.”[ 5 ] When Butler et al. (2022) evaluated the frequency of lumbar pSEH, they further concluded; “Treatment of pSEH consists of emergent hematoma evacuation as a delay in repeat surgery has a deleterious effect on neurological recovery.”[ 3 ] In short, this perspective presents the consensus opinion that for pSEH, early diagnosis and emergent surgery are essential to optimize neurological outcomes [ Tables 1 - 4 ].[ 1 - 3 , 5 , 8 - 10 , 13 ]

CONCLUSION

Symptomatic pSEH occur following 0.1%-4.46% of all spinal operations within an average of 2.7, to < 24 hrs (i.e., nearly 100% for cervical/thoracic, and 50% for lumbar lesions), to between 24-48 postoperative hrs. [ Tables 1 - 4 ].[ 1 - 18 ] The most critical factors to limit/avert permanent neurological sequelae of pSEH included; early recognition of new postoperative neurological deficits within these time frames, obtaining immediate/timely postoperative MR studies, and performing emergency spine surgery where indicated [ Tables 1 - 4 ].[ 1 - 18 ]

Declaration of patient consent

Patients’ consent not required as patients’ identities were not disclosed or compromised.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation

The author(s) confirms that there was no use of Artificial Intelligence (AI)-Assisted Technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

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