Gianluca Cinotti

Results of disc prosthesis after a minimum follow-up period of 2 years.

Study Design This study analyzed retrospectively 46 patients undergoing artificial disc replacement. Objective To assess the clinical and radiographic outcomes of patients who had Charitè SB III disc prosthesis. Summary of Background Data Results of disc prosthesis have been reported only at very short‐term follow‐up periods; preoperative diagnosis and criteria used to evaluate the clinical outcomes were not reported. Methods Forty‐six patients who had had a disc prosthesis were evaluated clinically and radiographically at least 2 years after surgery. Preoperative diagnosis included disc degeneration in 22 patients and failed disc excision in 24 patients. Disc prosthesis was implanted at a single vertebral level in 36 patients and at two levels in 10 patients. Follow‐up evaluation was performed after an average of 3.2 years (range, 2–5 years). Results Sixty‐three percent of patients reported satisfactory results. The success rate was 69% in patients who underwent isolated disc replacement and 77% in those with no previous back surgeries. Seven patients who had unsatisfactory results underwent posterolateral fusion without removing the artificial disc. Two patients underwent removal of the prosthesis. No failure of the implants or loosenings or wear of the polyethylene core were found. Vertebral motion averaged 9° at the operated levels and 16° at the adjacent levels. Conclusion A wrong surgical indication, rather than failure of the prosthesis, appears to be the main cause of unsatisfactory results of disc replacement at medium‐term evaluations. Prospective and longer term studies are needed to establish whether disc prosthesis may offer advantages compared with spinal fusion.

Pedicle instrumentation in the thoracic spine: A morphometric and cadaveric study for placement of screws

STUDY DESIGN In part 1 of the study, the morphometry of thoracic pedicles and bony landmarks for pedicle screw placement were evaluated. In part 2, pedicle screws were inserted in fresh cadavers, using a different entry point in the left and right pedicles. OBJECTIVES To identify the safest entry point and screw orientation for pedicle screws in the thoracic spine. SUMMARY OF BACKGROUND DATA A few morphometric investigations have been performed on thoracic vertebrae, but the safest technique for screw insertion in thoracic pedicles has not been analyzed. METHODS Mean, range, and standard deviations of pedicle transverse diameter and pedicle orientation were measured in 99 dried thoracic vertebrae. We evaluated the position of the bottom of the superior facet and that of the superior border of the transverse process in relation to the center of the pedicle. The relation between the pedicle axis and the superior facet in the frontal plane was also assessed. In part 2 of the study, pedicle screws were inserted in fresh cadavers at the intersection between the superior border of the transverse process and the middle of the superior facet (entry point A) and between the former and the lateral two thirds of the facet (entry point B). RESULTS The smallest transverse diameter was found at 16 (mean 4.3 mm) where pedicles measured less than 5 mm in 68% of the specimens. In the frontal plane, the pedicle axis intersected the middle of the superior facet in 15% of specimens, the lateral two-thirds in 62%, and the lateral border of the facet in 23%. Of the 126 screws inserted in fresh human cadavers, 15 (24%) of the screws inserted using entry point A and 10 (16%) of those inserted using entry point B violated the pedicle cortex (P > 0.05). Six (10%) of the screws inserted using entry point A compared with no screw inserted using entry point B penetrated the anterior vertebral cortex (P = 0.03). CONCLUSIONS Pedicles between T4 and T8 may not be wide enough for screw fixation. An entry point for pedicle screws located at the intersection between the superior border of the transverse process and the lateral two thirds of the superior facet seems more likely to be in line with the pedicle axis than do other entry points. In the lower thoracic vertebrae this entry point, in combination with insertion of the screws more medially oriented than the pedicle axis, significantly reduces the risk of violating the anterior vertebral cortex.

The surgical treatment of central lumbar stenosis. Multiple laminotomy compared with total laminectomy

We assigned 67 patients with central lumbar stenosis alternately to either multiple laminotomy or total laminectomy. The protocol, however, allowed multiple laminotomy to be changed to total laminectomy if it was thought that the former procedure might not give adequate neural decompression. There were therefore three treatment groups: group I consisting of 26 patients submitted to multiple laminotomy; group II, 9 patients scheduled for laminotomy but submitted to laminectomy; and group III, 32 patients scheduled for, and submitted to, laminectomy. The mean follow-up was 3.7 years. Bilateral laminotomy at two or three levels required a longer mean operating time than total laminectomy at an equal number of levels. The mean blood loss at surgery and the clinical results did not differ in the three groups. The mean subjective improvement score for low back pain was higher in group I but there was also a higher incidence of neural complications in this group. No patient in group I had postoperative vertebral instability, whereas this occurred in three patients in groups II and III, who had lumbar scoliosis or degenerative spondylolisthesis preoperatively. Multiple laminotomy is recommended for all patients with developmental stenosis and for those with mild to moderate degenerative stenosis or degenerative spondylolisthesis. Total laminectomy is to be preferred for patients with severe degenerative stenosis or marked degenerative spondylolisthesis.

Ligamenta flava in lumbar disc herniation and spinal stenosis. Light and electron microscopic morphology.

Methods. Ligamenta flava obtained from nine patients with lumbar disc hernlation and ten patients with lumbar stenosis were studied at histologic, histochemical, and ultrastructural levels. Lumbar ligaments flava removed from six patients who underwent surgeries for thoracolumber fractures were used as controls. Results. Ligements flave from control subjects consisted of large elastic fibers, thin bundles of collagen fibers, and few spindle-shaped fibroblasts In proximity to the laminal insertion the ligaments had fibrocarilagireous features. In the control subjects who were age 50 or older, the cells decreased in number and areas that had fewer and thinner elastic fibers and a more abundant collagen component were visible occasionally. In patients with disc herniation, the ligaments had similar morphologic features to those of the controls of similar ages. The ligamenta flava from patients with lumbar stenosis showed areas of fibrosis in which the cells were often represented by actively synthesizing fibroblests and areas of chondroid metaplasia. Degenerating elastic fibres were seen occasionally while calcified areas were observed often. Conclusions. Ligamenta flava undergo slight fibrotic and chondrometaplastic changes with aging. No peculiar changes occur in patients with disc herniation. In spinal stenosis, fibrotic changes, chondroid metaplasia, and calcification reduce the dencity of the ligaments, which may thus bulge into the spinal canal in the standing position even if they are normal in thickness.

Stenosis of lumbar intervertebral foramen: anatomic study on predisposing factors.

Study Design. In Study 1 the authors measured the vertical and sagittal dimensions of the intervertebral foramen in dried lumbar vertebrae. In Study 2 the dimensions of the intervertebral foramen were measured in fresh cadaveric spines in which the soft tissues forming the foraminal walls were preserved. Objectives. To investigate whether disc narrowing, or other factors related to the morphometry of lumbar vertebrae, may predispose to foraminal stenosis. Summary of Background Data. Predisposing factors to foraminal stenosis have been little investigated. Previous studies suggested that narrowing of the disc space might cause a reduction in the foraminal dimensions; however, it is not clear whether such a reduction is to such an extent as to compress the nerve root within the foramen. Methods. In Study 1 the vertical and sagittal dimensions of 160 intervertebral foramens were measured on dried white spines. Measurements were performed in the presence of a normal height of the disc space, obtained using a silicone rubber disc, and repeated in the same specimen after disc removal. Foraminal dimensions were then related to the sagittal diameter of the spinal canal and the pedicle length. In Study 2, the authors evaluated the dimensions of 50 intervertebral foramens of fresh cadaveric spines, in which the soft tissues forming the foraminal walls and the nerve root were preserved. In specimens showing normal or slightly decreased disc height, the foraminal dimensions were measured before and after disc excision. Results. In Study 1 the reduction in the foraminal height after disc removal was, on average, 6.5 mm (P < 0.0001). In both Studies 1 and 2 the sagittal dimensions of the foramen were not significantly reduced after disc removal. No significant difference was found in Study 1 in the sagittal dimensions of the foramen between specimens showing normal or degenerated facet joints. In Study 2 a compression of the nerve root within the foramen was found in one specimen, showing a concomitant central stenosis at multiple levels. A significant correlation was found between the sagittal diameters of the foramen and the sagittal diameter of the spinal canal and the pedicle length. Conclusions. Narrowing of the disc space significantly reduces the vertical diameter of the foramen but has no significant effects on its sagittal dimensions. In contrast, the sagittal dimensions of the foramen are strictly related to the sagittal diameter of the spinal canal and the pedicle length. These results suggest that in patients with developmental or combined stenosis of the central spinal canal, a concomitant foraminal stenosis is likely to be present, or at least should be suspected.

Contralateral recurrent lumbar disc herniation. Results of discectomy compared with those in primary herniation.

STUDY DESIGN The surgical outcomes of patients who underwent discectomy for contralateral recurrent herniation and primary herniation were evaluated. OBJECTIVE To assess whether the clinical results in patients undergoing surgery for contralateral recurrent disc herniation may be as good as those reported after primary discectomy. SUMMARY OF BACKGROUND DATA No retrospective or prospective investigation has been conducted on the surgical treatment of contralateral recurrent lumbar disc herniation. METHODS Sixteen patients who underwent surgery for recurrent disc herniation at the same level as primary disc excision, but on the opposite side, were analyzed prospectively from the recurrence of contralateral radicular pain (Group 1). All patients had reported a satisfactory results after primary discectomy. Fifty consecutive patients who underwent disc excision during the study period, who did not report recurrent radicular pain, were analyzed for comparison (Group 2). Overall patient satisfaction, pain severity, functional outcome, and work status were evaluated. RESULTS At the 2-year follow-up, the clinical outcome was rated as satisfactory in 14 of 16 patients in Group 1 and in 45 of 50 in Group 2 (P > 0.05). Twelve patients in Group 1 and 42 in Group 2 had resumed their work or daily activities at the same level as before the operation (P > 0.05). Radicular pain was significantly improved in both groups at the 6-month and 2-year follow-ups. At the 6-month follow-up, low back pain was significantly improved only in the patients in Group 2; however, at the 2-year follow-up, low back pain was significantly improved in both groups. CONCLUSIONS Clinical results in patients reoperated on for contralateral recurrent lumbar disc herniation compare favorably with those reported after primary discectomy. The improvement of pain in the low back and lower limbs reported by the majority of patients 2 years after reoperation suggests that fusion is not needed in this patient population.

Degenerative changes of porcine intervertebral disc induced by vertebral endplate injuries.

Study Design. Graded endplate injuries were performed in porcine lumbar discs. The effects of such injuries were compared to control animals in which a sham operation was performed. Objectives. To investigate the effects of endplate injuries on disc tissue. Summary of Background Data. Studies have shown that injuries of vertebral endplates are frequently found at autopsy. However, little is known on the effects of acute injuries of vertebral endplates in vivo. Methods. Ten domestic pigs were included in the study group. Under general anesthesia, the lower three discs of the lumbar spine were exposed and randomly submitted to multiple endplate injuries, isolated endplate injury, and no treatment. A sham operation was performed in 5 pigs used as control group. Animals were killed 7 months after surgery and the harvested lumbar spine submitted to MRI investigations, histologic, and biochemical analysis. Results. MRI showed that all but one discs treated with multiple endplate injuries were markedly degenerated while, of the discs treated with an isolated injury, one was markedly degenerated, five slightly degenerated and two were normal (P = 0.01). Histologic analysis showed severe changes in discs treated with multiple injuries. In those who had an isolated injury, changes were less severe and essentially limited to the posterior anulus or the inner anterior anulus. Biochemical analysis showed an inverse correlation between uronate content in the nucleus pulposus and severity of endplate injuries. Conclusions. Injuries of vertebral endplates in porcine discs were found to cause degenerative changes in the disc tissue on MRI, histologic, and biochemical investigations. The severity of such degenerative changes was related to the severity of endplate injuries. Injuries of vertebral endplate may be one of the pathomechanisms leading to early changes in the disc matrix and eventually to abnormal biomechanical behavior of the whole disc. The present animal model seems to be a suitable experimental model for disc degeneration.

Management of complex elbow instability.

Complex elbow instability is a challenging injury even for expert elbow surgeons. The preoperative radiographs should be carefully evaluated to recognize all lesions that may occur in complex elbow instabilities. Recognizing all the possible lesions is critical to achieve an optimal outcome. The most common types of injuries are as follows: (1) radial head fractures associated with lateral and medial collateral ligaments lesions (with or without elbow dislocation); (2) Coronoid fractures and lateral collateral ligament lesion (with or without elbow dislocation); (3) Terrible Triad; (4) Transolecranon fracture-dislocation; (5) Monteggia-like-lesions; and (6) Humeral Shear fractures associated with lateral and medial collateral ligaments lesions (with or without elbow dislocation). A correct evaluation includes X-rays, CT scan with 2D and 3D reconstruction and stability test under fluoroscopy. The treatment is always surgical and is challenging, and outcomes are not predictable. The goals of treatment are (1) to perform a stable osteosynthesis of all fractures, (2) to obtain concentric and stable reduction of the elbow and (3) to allow early motion. The proximal ulna must be anatomically reduced and fixed; the radial head must be repaired or replaced, and the coronoid fractures must be repaired or reconstructed. With respect of soft tissue lesions, the LUCL must be reattached with suture anchors or trans-osseous suture. The next critical step is the intra-operative assessment of elbow stability. If the elbow remains unstable, MCL repair and/or application of hinged external fixator must be considered. The most recent clinical and experimental studies have significantly expanded our knowledge of elbow instability and its management. Definite treatment protocols may improve the clinical results of such complex injuries.

Ipsilateral recurrent lumbar disc herniation

We analysed prospectively 26 patients who had revision operations for ipsilateral recurrent radicular pain after a period of pain relief of more than six months following primary discectomy. They were assessed before the initial operation, between the two procedures and at a minimum of two years after reoperation. MRI was performed before primary discectomy and reoperation. Fifty consecutive patients who had a disc excision during the study period but did not have recurrent radicular pain, were analysed as a control group. Of the study group 42% related the onset of recurrent radicular pain to an isolated injury or a precipitating event, but none of the control group did so (p < 0.001). T2-weighted MRI performed before primary discectomy showed that patients in the study group had significantly more severe disc degeneration compared with the control group (p=0.02). Intraoperative findings revealed recurrent disc herniation in 24 patients and bulging of the disc in two, one of whom also had lateral stenosis. Epidural scarring was found to be abundant, intraoperatively and on MRI, in eight and in nine patients, respectively. At the last follow-up, the clinical outcome was satisfactory in 85% of patients in the study group and in 88% of the control group (p > 0.05). Work or daily activities had been resumed at the same level as before the onset of symptoms by 81% of the patients in the study group and 84% of the control group. No correlation was found between the amount of epidural fibrosis, as seen intraoperatively and on MRI, and the result of surgery. The recurrence of radicular pain caused no significant changes in the psychological profile compared with the assessment before the primary discectomy.

The morphometry of the coracoid process – its aetiologic role in subcoracoid impingement syndrome

Abstract Anatomical morphometric studies of the coracoid process and coraco-glenoid space were carried out on 204 dry scapulae. No statistically significant correlations were found between length, or thickness of the coracoid process, prominence of the coracoid tip, coracoid slope, coraco-glenoid distance, or position of the coracoid tip with respect to the uppermost point of the glenoid. These anatomical characteristics were independent of the dimensions of the scapulae. Three configurations of the coraco-glenoid space were identified. Type I configuration was found in 45% of scapulae and Type II and Type III, in 34% and 21% of specimens, respectively. The lowest value of the coraco-glenoid distance were seen in Type I scapulae. Morphometric characteristics which might predispose to subcoracoid impingement were found in 4% of Type I scapulae. A total of 27 scapulae, nine with each type of configuration were submitted to CT scanning. Scapulae with a Type I configuration were found to have low values for the coraco-glenoid angle and coracoid overlap, which are known to be associated with a short coraco-humeral distance. Subjects with a Type I configuration, and severe narrowing of the coraco-glenoid space, appear to be predisposed to coraco-humeral impingement. These morphometric characteristics may be easily evaluated on CT scans.Résumé Des études d’anatomie morphométrique du processus coraco ont été menées sur 204 omoplates sèches. Aucune corrélation statistiquement significative n’a été trouvée entre la longueur, ou l’épaisseur, du processus coraco, la proéminence du point coraco, la pente coraco, la distance coracogléno et la position du point coraco par rapport au sommet de la gléno. Ces caractéristiques sont indépendantes des dimensions de l’omoplate. Trois configurations de l’espace coracogléno ont été identifiées: Type I, Type II et Type III. Les caractéristiques morphometriques qui peuvent prédisposer à une friction subcoraco ont été trouvées sur 4% des omoplates avec une configuration de Type I. Un total de 27 omoplates, 9 de chaque type de configuration, a été soumis à une tomographie osseuse. Les omoplates du premier type de configuration présentent un angle coracogleno de faible valeur, ce qui est connu pour être associé avec une distance coracohumerale faible. Les sujets présentant une configuration de premier type et un sévère rétrécissement de l’espace coracogleno, apparaissent être prédisposés à une friction coracohumérale. Ces caractéristiques morphométriques peuvent aisément être évaluées par tomographie osseuse.