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Unique Complications of Percutaneous Endoscopic Lumbar Discectomy and Percutaneous Endoscopic Interlaminar Discectomy.

BACKGROUND
Percutaneous endoscopic discectomy (PED) includes 2 main procedures: percutaneous endoscopic lumbar discectomy (PELD) and percutaneous endoscopic interlaminar discectomy (PEID), both of which are minimally invasive surgical procedures that effectively deal with lumbar degenerative disorders. Because of the challenging learning curve for the surgeon and the individual characteristics of each patient, preventing and avoiding complications is difficult. The most common complications, such as nucleus pulposus omission, nerve root injury, dural tear, visceral injury, nerve root induced hyperalgesia or burning-like nerve root pain, postoperative dysesthesia, posterior neck pain, and surgical site infection, are difficult to avoid; however, more focus on these issues perioperatively may be in order. Additionally, unique and unexpected complications can also occur, such as retroperitoneal hematoma (RPH), intraoperative seizures, and thrombophlebitis, among others.


OBJECTIVE
We aim to delineate unique complications during PED and accumulate strategies to prevent significant morbidity and improve surgical techniques.


STUDY DESIGN
A retrospective cohort study of patients undergoing PEID or PELD from October 2014 to January 2016.


SETTING
Affiliated hospitals of Qingdao University.


METHODS
Patients with lumbar disc herniation (LDH) who underwent PEID and PELD were retrospectively analyzed. Complications were recorded and analyzed pre and postoperatively. We assessed clinical outcomes using the visual analog scale (VAS) and Oswestry Disability Index (ODI) and classified the results into "excellent," "good," "fair," or "poor" based on the modified MacNab criteria. All of the patients were followed for more than one year to evaluate their recovery from complications.


RESULTS
From October 2014 to January 2016, 426 patients with LDH underwent PEID (106 cases) or PELD (320 cases). Common complications and occurrence rates were as follows: the incomplete removal of herniated discs was 1.4% (6/426), recurrence 2.8% (12/426), nerve root injury 1.2% (5/426), dural tear 0.9% (4/426), and nerve root induced hyperalgesia or burning-like nerve root pain 2.3% (10/426); no posterior neck pain or surgical site infection occurred. Unique complications included: passage of the working channel through the spinal canal into the disc space (one case), super-elastic nerve hook caught by exiting nerve root (one case), epidural hematoma (one case), radicular artery injury and massive bleeding (one case) which was revised by micro-endoscopic discectomy, and intraoperative seizure (one case). No serious consequences occurred after active medical intervention, and most patients had good recovery by 3 months postoperatively with physical therapy.


LIMITATIONS
The main limitations of this study are the retrospective study design, limited case number, and short follow-up period.


CONCLUSIONS
PEDs are effective and minimally invasive methods for the surgical treatment of LDH, causing fewer complications due to the very minimal operational trauma for the muscle-ligament complex and stability of the spine. Nevertheless, because of the difficult learning curve for surgeons, lack of experience with the requisite surgical techniques, and enhanced clinical responsibility, a variety of problems may occur. Especially concerning are the unique complications mentioned here, which potentially lead to severe injury for the patient and require diligent preventive measures.


KEY WORDS
Unique complications, epidural, hematoma, interlaminar, transforaminal, PEID, PELD.