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CC BY 4.0 · J Neuroanaesth Crit Care
DOI: 10.1055/s-0045-1809410
Case Report

Persistent Headache from Pneumocephalus after Spinal Tumor Excision—A Case Report

Prachi Sharma 
1   Department of Neuro-anaesthesia and Critical Care, Max Super Speciality Hospital, New Delhi, India
,
Sarika Juneja 
1   Department of Neuro-anaesthesia and Critical Care, Max Super Speciality Hospital, New Delhi, India
,
Kavita Sandhu 
1   Department of Neuro-anaesthesia and Critical Care, Max Super Speciality Hospital, New Delhi, India
› Author Affiliations
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Abstract

Pneumocephalus following spinal surgery is a rare but significant complication, particularly in procedures involving durotomy. Its nonspecific presentation can be mistaken for anesthesia-related effects, delaying diagnosis. We report a 70-year-old female who underwent D4 laminectomy and excision of a D3–D4 intradural extramedullary tumor. In the immediate postoperative period, she developed progressively worsening frontal headache and nausea, unresponsive to standard analgesia. A computed tomography scan on postoperative day 1 revealed pneumocephalus in the basal cisterns and Sylvian fissures. Despite no evident cerebrospinal fluid leak after watertight closure or intraoperative nitrous oxide use, factors such as subtle dural microleaks, intraoperative head elevation, and the use of a subfascial drain may have contributed to intracranial air entry. Vacuum activation of the drain, though not confirmed, could not be ruled out. Conservative management with supine positioning, oxygen therapy, analgesics, and early drain removal led to full symptom resolution. This case highlights the need for early recognition of pneumocephalus in patients with severe postoperative headache particularly as headache severity has been shown to correlate with the extent of pneumocephalus. Heightened awareness and preventive intraoperative strategies are essential to mitigate this risk.


 

Keywords

pneumocephalus - laminectomy - spine surgery - headache

Introduction

Pneumocephalus due to spinal causes though reported, is rare. However, spinal surgeries necessitating durotomy may precipitate dural tears and subsequent cerebrospinal fluid (CSF) leaks, leading to air entrainment into the subarachnoid space and eventual intracranial air accumulation. The reported incidence of dural tears during spine surgeries varies from 0.3 to 5.9%,[1] with dural tears culminating into symptomatic pneumocephalus being even more infrequent.[2] The nonspecific nature of symptoms associated with pneumocephalus pose additional diagnostic challenge postspinal surgeries, as they predominantly manifest as headache, nausea, vomiting, and lethargy, which may initially be misconstrued as sequelae of anesthesia. We present the case of a patient who developed persistent headache following surgery for a dorsal intradural extramedullary (IDEM) tumor, which was later diagnosed as pneumocephalus.


 

Case Report

A 70-year-old female presented with bilateral leg pain associated with claudication and paresthesias of all four limbs (lower limbs more than upper limbs). She was diagnosed with a D3-D4 IDEM tumor and underwent D4 laminectomy and tumor excision. The patient was induced with weight-appropriate doses of propofol, fentanyl, and rocuronium, and was maintained with propofol and fentanyl infusions (with as-needed boluses of rocuronium) in the prone position. Nitrous oxide was not used in this case. The patient remained hemodynamically stable till durotomy, when blood pressure (BP) suddenly dropped from 124/72 to 70/44 mm Hg and then to 62/38 mm Hg. This was not associated with any changes in heart rate, peak pressures, or end-tidal carbon dioxide values. This transient drop lasted for less than a minute as immediate intervention with crystalloids and intravenous mephentermine in aliquots of 3 + 3 mg was instituted. The BP picked up and subsequently, the patient remained stable hemodynamically for the rest of the procedure. No overt CSF leak or collection was observed at the surgical site postoperatively. A watertight dural closure was achieved primarily and augmented with glue. A Valsalva maneuver was performed intraoperatively to ensure no CSF leak. Toward the end of the surgery, a subfascial drain was inserted to facilitate gravity drainage of the surgical site. The patient was reversed and trachea extubated without any delay in recovery.

In the immediate postoperative period, the patient complained of headache despite being on fentanyl infusion at 30 mcg/ hour. She also complained of on and off episodes of nausea. These episodes were managed with intravenous paracetamol 1 g and intravenous ondansetron 4 mg. The visual analog scale (VAS) score subsequently decreased from 5 to 2. However, as fentanyl infusion was tapered, the patient experienced a persistent headache localized to the frontal and retro-orbital region due to which the opioid infusion had to be increased to 50 mcg/hour. As the patient continued to complain of pain with the VAS score exceeding 5 on postop day 1, a computed tomography (CT) scan was ordered, which showed bilateral Sylvian, and basal cisternal hypodensities suggestive of pneumocephalus ([Fig. 1]), for which the patient was managed with hydration, supine positioning, oxygen therapy, and round-the-clock paracetamol and intravenous fentanyl, which was later transitioned to a fentanyl 50 mcg patch. In the absence of explicit documentation, it was difficult to ascertain whether the vacuum drain had been unintentionally activated. Thus, once pneumocephalus was diagnosed on postoperative CT, the subfascial drain was promptly discontinued to eliminate any ongoing negative pressure and prevent further intracranial air entry. The patient was discharged 3 days postsurgery based on symptom resolution, hemodynamic stability, and absence of new neurological findings. A follow-up visit in the outpatient department 3 weeks postdischarge revealed no new deficits.

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Fig. 1 Noncontrast computed tomography (CT) scan of the head showing (A) bilateral Sylvian, (B) right Sylvian, (C) basal cisternal (suprasellar), and (D) cerebellopontine cistern hypodensities (blue arrows) suggestive of pneumocephalus.

 

Discussion

Pneumocephalus is more commonly seen in patients with craniofacial tumors, trauma, and infectious etiologies.[3] Our patient was diagnosed with symptomatic pneumocephalus after undergoing spinal surgery. Among the spinal causes, dural injury during surgery can lead to CSF leak and thus predispose to iatrogenic pneumocephalus.[4] However, such reports remain rare. Nonetheless, as surgeries for IDEM tumor excision require dural opening, iatrogenic air entrainment from CSF loss can occur.

The occurrence of pneumocephalus after spinal surgery could be attributed to following factors. First, the inverted pop bottle mechanism during durotomy can predispose to the generation of a negative intracranial pressure to prevent further CSF loss, until sufficient air enters to equilibrate this loss.[1] The “enhanced inverted soda bottle mechanism” has been described in literature primarily in the context of lower spinal dural defects. In such cases, the typical mechanism is amplified by posture, anatomical positioning, and pressure dynamics resulting in more rapid or severe pneumocephalus.[5] If, during or after durotomy, the patient's head is elevated, it increases the gravitational pull on CSF, exaggerating downward flow and promoting a siphoning effect. This can facilitate the ascent of air into the cranial cavity, particularly if the head-elevated position is maintained for a prolonged duration. Second, the suction drain in the postoperative period can potentially enable air ingress into the subarachnoid space following a meningeal breach during surgery.[6] Continuous aspiration can exacerbate CSF loss through the dural defect, promoting a sustained negative pressure that facilitates further air entry into the intracranial space. Third, a ball-valve mechanism can facilitate air entry while impeding its exit from the cranial cavity, especially when the patient is placed in a head-elevated position.[1] In the ball-valve mechanism, air accumulates in the cranial cavity due to a pressure gradient that favors inward air movement. This typically happens when pressure outside the skull becomes greater than the pressure inside, especially in the presence of a dural breach. Situations that acutely raise intrathoracic or sinus pressure such as a Valsalva maneuver can force air through this dural defect into the intracranial space. Once inside, the intracranial structures may plug the defect, preventing the trapped air from escaping, thus creating a one-way valve effect and leading to progressive air buildup. While a watertight dural closure was achieved in our case, even minor, undetected microleaks can be sufficient for air entry.

Besides this, the prone position during surgery can lead to elevated intra-abdominal pressure and consequently raise intracranial pressure, which may open up undetected defects near the cribriform plate.[7] Although rare, clival defects may serve as an anatomical conduit for intracranial air entry in spinal surgeries, especially in the setting of a dural breach. In a recent case report by Al Abdallat et al, a patient developed tension pneumocephalus following scoliosis correction surgery, where imaging incidentally revealed a clival bony defect in the absence of CSF rhinorrhea or overt leak.[8] While the exact mechanism remained uncertain, the authors proposed that the clival defect may have facilitated air ingress into the cranial cavity, highlighting the potential role of such anatomical variants in postoperative pneumocephalus.[8]

Anatomically, pneumocephalus often accumulates in the frontal region, likely because it is the highest point in supine position and has a thinner dura that is firmly adhered to the bone. Therefore, the presence of frontal location of headache, as in our patient, warrants a high index of suspicion, and pneumocephalus should be included in the differential diagnosis, particularly in cases involving durotomy. In a study conducted by Nam et al, it was observed that patients without pneumocephalus did not report postoperative headaches and there was a statistically significant relationship between the severity of pneumocephalus and the occurrence of postoperative headaches.[9] They proposed a classification based on the extent of air in the intracranial cavity,[9] according to which our patient had moderate pneumocephalus, with evidence of air in the basal cisterns but not in the extra-axial compartment. Such a classification has clinical significance, as the severity of headaches increases with the extent of pneumocephalus. This classification can aid in early anticipation and interpretation, facilitating prompt management.

We did not repeat brain CT scans to monitor pneumocephalus at regular intervals due to concerns about radiation exposure, and there are no established guidelines on the recommended frequency of these scans.[10] Typically, improvement begins within 24 to 48 hours, with full resolution in 2 to 3 weeks.[11]

To minimize the risk of pneumocephalus during spinal surgery, several surgical strategies are essential. A meticulous, watertight dural closure should be achieved using primary sutures reinforced with tissue adhesives. A Valsalva maneuver may be performed intraoperatively to detect subtle CSF leaks. The dural sac should be irrigated with saline prior to closure, and suction pressures must be carefully regulated to prevent excessive CSF drainage. The use of vacuum drains may be discouraged in cases where an intraoperative dural breach has been identified, as these can create a negative pressure gradient that further promote intracranial air entry. Maintaining the patient's head in a dependent position relative to the surgical field and limiting operative time can further reduce the risk of air ingress. Particular caution is warranted with prone positioning, which can elevate intracranial pressure and enable air entry through undetected dural microtears, underscoring the importance of intraoperative vigilance and thorough inspection. From an anesthetic perspective, nitrous oxide should be avoided, as it can diffuse into and expand trapped intracranial air. This precaution is especially important in procedures where a dural breach is possible.

In conclusion, pneumocephalus, though an uncommon complication of spinal surgeries, should be actively considered in the differential diagnosis of persistent postoperative headache in cases involving durotomy. Our case illustrates that intracranial air can accumulate even in the absence of overt CSF leak or visible dural compromise, possibly due to subtle mechanisms such as intraoperative head elevation, negative pressure from surgical drains, or unrecognized microleaks. A frontal or bifrontal headache, especially when disproportionate to the expected postoperative course and unresponsive to standard analgesia should prompt early imaging to evaluate for pneumocephalus. Our experience underscores the importance of meticulous surgical technique, cautious use of subfascial drains, and heightened awareness among perioperative teams regarding this underrecognized but clinically relevant entity.


 

 

Conflict of Interest

None declared.


Address for correspondence

Prachi Sharma, DM
Department of Neuro-anaesthesia and Critical Care, Max Super Speciality Hospital
Saket, Press Enclave Marg, New Delhi 110017
India   

Publication History

Article published online:
03 July 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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Zoom
Fig. 1 Noncontrast computed tomography (CT) scan of the head showing (A) bilateral Sylvian, (B) right Sylvian, (C) basal cisternal (suprasellar), and (D) cerebellopontine cistern hypodensities (blue arrows) suggestive of pneumocephalus.