We report a series of epidural hematomas which cause neurologic deterioration after spinal surgery, and have taken risk factors and prognostic factors into consideration. We retrospectively reviewed the database of 3720 cases of spine operation in a single institute over 7 years (1998 April- 2005 July). Nine patients who demonstrated neurologic deterioration after surgery and required surgical decompression were identified. Factors postulated to increase the postoperative epidural hematoma and to improve neurologic outcome were investigated. The incidence of postoperative epidural hematoma was 0.24%. Operation sites were cervical 3 cases, thoracic 2 cases, and lumbar 4 cases. Their original diagnoses were tumor 3 cases, cervical stenosis 2 cases, lumbar stenosis 3 cases and herniated lumbar disc 1 case. The symptoms of epidural hematomas were neurologic deterioration and pain. After decompression, clinical outcome revealed complete recovery in 3 cases (33.3%), incomplete recovery in 5 cases (55.6%) and no change in 1 case (11.1%). Factors increasing the risk of postoperative epidural hematoma were coagulopathy from medical illness or anticoagulation therapy (4 cases, 44.4%) and highly vascularized tumor (3 cases, 33.3%). The time interval to evacuation of complete recovery group (29.3 hours) was shorter than incomplete recovery group (66.3 hours). Patients with coagulopathy and highly vascularized tumor were more vulnerable to spinal epidural hematoma. The postoperative outcome was related to the preoperative neurological deficit and the time interval to the decompression.

Retrospective study of the difference of heterotopic ossification (HO) occurrence according to 3 different types of prosthesis. This study was designed to investigate the difference of HO occurrence according to different type of prosthesis. HO is defined as formation of the bone outside the skeletal system. Reported HO occurrence rate in cervical artificial disc replacement (ADR) was unexpectedly high and varied. But the influencing factors of HO in cervical ADR have not been elucidated well. The prosthesis-related factors for making difference of HO occurrence were investigated in this study. A total of 170 patients undergoing cervical arthroplasty with the Bryan cervical disc prosthesis (Medtroic Sofamor Danek, Memphis, TN), Mobi-C disc prosthesis (LDR Medical, Troyes, France), and ProDisc-C (Synthes, Inc., West Chester, PA) were included. Cervical lateral radiographs obtained before and after surgery were used to identify HO. Occurrence rate, occurrence-free period, location, and grade of HOs were investigated according to the different prosthesis. Each prosthesis group included patients as follows: Bryan disc, 81 patients; Mobi-C, 61 patients; and ProDisc-C, 28 patients. Overall HO rate was 40.6% (69 of 170 patients). Each HO occurrence rate by prosthesis was as follows: the Bryan disc group, 21.0%; Mobi-C group, 52.5%; and the ProDisc-C group, 71.4%. In the survival analysis, all patients showed 27.1 +/- 3.7 months as the median survival. The Bryan disc group showed statistically longer survival (48.4 +/- 7.4 months) than the other groups. Occurrence of HO is an inevitable postoperative complication after cervical ADR. The occurrence rate of HO was higher than our expectation. Moreover, definite differences in occurrence rate according to the prosthesis type were identified by this study.

A prospective analysis. The purpose of this study was to compare the clinical and radiologic outcomes of cervical artificial disc replacement (C-ADR) combined with anterior cervical discectomy and fusion (ACDF) and 2-level ACDF in patients with 2-level cervical disc disease. Adjacent segment degeneration is a long-term complication of ACDF, and estimated to affect 25% of patients within 10 years of the initial surgery. Two-level fusion leads to a substantially greater increase in intradiscal pressure than one-level fusion. It has been demonstrated that C-ADR maintains motion at the level of the surgical procedure and decreases strain on the adjacent segments for prevention of adjacent segment degeneration. In the case of 2-level cervical disc disease, hybrid surgery (HS), consisting of C-ADR combined with ACDF, may be a reasonable alternative to 2-level ACDF (2-ACDF). Between 2004 and 2006, 40 patients undergoing 2-level cervical disc surgery at our hospital were identified who met the following surgical indications: 2 consecutive level degenerative disc disease between C3/4 and C6/7; either a radiculopathy or myelopathy; and no response to conservative treatment for >6 weeks. Twenty patients of the HS group were matched to 20 patients of the 2-ACDF group based on age and gender. Patients were asked to check the neck disability index (NDI) and grade their pain intensity before surgery and at routine postoperative intervals of 1, 3, 6, 12, and 24 months. Dynamic flexion and extension lateral cervical radiographs were obtained in the standing position before surgery and at routine postoperative intervals of 1, 3, 6, 12, and 24 months. The angular range of motion (ROM) for C2–C7 and adjacent segments were measured using the Cobb method with PACS software. The HS group had better NDI recovery 1 and 2 years after surgery (P < 0.05). Postoperative neck pain was less in the HS group 1 month and 1 year after surgery (P < 0.05). There was no difference in arm pain relief between the groups. The HS group showed faster C2–C7 ROM recovery. The mean C2–C7 ROM of the HS group recovered to that of the preoperative value, but that of the 2-ACDF group did not (P < 0.05). The inferior adjacent segment ROM showed significant differences between the groups 6 and 9 months, and 1 and 2 years after surgery (P < 0.05, P < 0.01, P < 0.05, and P < 0.05, respectively). HS is superior to 2-ACDF in terms of better NDI recovery, less postoperative neck pain, faster C2–C7 ROM recovery, and less adjacent ROM increase.

Kim D, et al. Yonsei Med J. 2017 Mar;58(2):453-457. https://doi.org/10.3349/ymj.2017.58.2.453