Clinical study
Risk factors of meralgia paresthetica after prone position surgery: Possible influence of operating position, laminectomy level, and preoperative thoracic kyphosis

https://doi.org/10.1016/j.jocn.2021.05.022Get rights and content

Highlights

  • Postoperative MP occurs with a higher incidence after spinal surgery than after craniotomy.

  • Thoracic and lumbar laminectomies are associated with a higher incidence of MP than the other.

  • The preoperative TK is significantly greater in patients with than in those without MP.

Abstract

Obesity and a prolonged surgical duration are reported risk factors for meralgia paresthetica (MP) after prone position surgery; however, this fails to explain why MP seldom occurs after prone position craniotomy. We reviewed the incidence of MP after spinal surgery and craniotomy in the prone position and investigated whether unidentified factors are involved in the mechanism of postoperative MP. Between January 2014 and March 2020, we performed 556 prone position surgeries. We excluded patients aged ≤16 years and those who were comatose or who required redo-surgery, and reviewed 446 eligible patients (124 who underwent craniotomies and 322 who underwent posterior spinal surgeries). Postoperative MP occurred in 46 (10.3%) patients with a higher incidence after spinal surgery than after craniotomy (13.7% vs. 1.6%, p < 0.001). Among the 322 patients who received posterior spinal surgery, thoracic and lumbar laminectomies were associated with a higher incidence of MP than cervical laminectomy. Analyses limited to those patients who received thoracic and lumbar laminectomies revealed that the preoperative thoracic kyphosis (TK) angle was significantly greater in patients with MP than in those without MP (average TK angle, 38.9° vs. 23.1°; p < 0.001), and that the preoperative lumbar lordosis angle did not significantly differ between the two groups. Apart from the known predisposing factors, we found that thoracolumbar-sacral laminectomy in patients with a greater TK angle is also a risk factor for MP after prone position surgery.

Introduction

Prone positioning is commonly used for occipital/suboccipital craniotomy and posterior spinal surgery; however, it is associated with several complications, including excessive intraoperative bleeding arising from increased venous pressure [1]. To reduce the venous pressure, various fixation instruments have been used to avoid abdominal compression [2], [3]. One of the common features of these instruments is the bilateral bodyweight support at the anterior portions of the iliac bone. However, this may cause postoperative meralgia paresthetica (MP) due to the mechanical compression of the iliac bone [1], [4], [5], [6], [7], [8]. MP is characterized by dysesthesia and a burning sensation in the anterolateral thigh with varying degrees of numbness. It can result from the compression of the anterior superior iliac spine in 10% to 20% of patients undergoing posterior spinal surgery [6], [7], [8]. Although it usually has a benign course, the symptoms can last for longer than a year [7]. Risk factors for MP include degenerative spinal disorders, obesity, and a prolonged surgical duration [8]. However, as per general clinical practice, it has been observed that MP seldom occurs after craniotomy in the prone position, although the reason remains unclear. We aimed to retrospectively analyze prone position surgeries performed at our institution to evaluate the mechanism of and risk factors for postoperative MP.

Section snippets

Patient enrollment and characteristics

This study was approved by the ethics committee of Saitama Medical Center/Saitama Medical University (No. 2364). The requirement for written informed consent was waived because of the retrospective design, and an opt-out choice was available to the patients on our hospital homepage. Between January 2014 and March 2020, 556 consecutive prone position surgeries were performed at the neurosurgical department of our institute. The anonymized data presented in this study are available upon request

Results

Table 1 summarizes the patient demographics. Among the 446 patients included in the study, 322 (72.2%) and 124 (27.8%) patients underwent posterior spinal surgery and craniotomy in the prone position, respectively. MP occurred in 46 (10.3%) of them. All the patients with MP received conservative treatment, which resulted in complete recovery within 6 months.

Table 2 presents the results of univariate analyses for factors associated with the incidence of MP. Age, sex, a history of diabetes

Discussion

MP is one of the postoperative complications caused by prone positioning. However, our findings revealed that the risk for MP after craniotomy in the prone position was extremely small. Moreover, thoracic and lumbar surgeries were associated with a significantly higher risk of postoperative MP than cervical surgeries. Among the patients who underwent thoracic laminectomy in our cohort, the risk of MP was associated with a greater preoperative degree of TK.

It is well known that MP can occur

Conclusion

Based on the present and previous findings, the risk of developing MP after prone position surgery is significantly higher after spinal surgery than after craniotomy. Although MP is considered a relatively benign complication after posterior spinal surgery, it should be noted that thoracolumbar-sacral surgery and preoperative greater TK degree are associated with an increased risk of MP after prone position surgery.

Sources of support

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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