Petros Christophis

Objectification of cranial vault correction for craniosynostosis by three-dimensional photography.

PURPOSE Correction of craniosynostosis is necessary in predominant cases. Surgical planning usually requires a preoperative CT to estimate the bony and intracerebral structures. A postoperative CT scan would involve a significant dose of radiation, which carries an elevated risk of malignant tumor development in later life. This study was performed to demonstrate the quality of three-dimensional (3D) photogrammetry when objectifying perioperative changes in craniofacial surgery. PATIENTS AND METHODS Twenty-eight patients with different premature craniosynostoses were analyzed photogrammetrically before and after surgical correction. 3D changes in cranial distances, symmetry and volumes were evaluated. A statistical covariance analysis excluded changes in cranial shape caused by physiological head growth. RESULTS The Cephalic Index in Scaphocephaly changed from 75.1% to a median value of 77.4%. The anterior symmetry ratio for coronal synostoses improved from 0.943 to 0.949 (a value of 1.0 represents perfect symmetry). The posterior symmetry ratio improved from 0.733 to 0.808 postoperatively in one single lambdoidal synostosis. In trigonocephaly, the median anterior skull volume rose from 528 to 601 ml. CONCLUSIONS 3D photogrammetry has great potential to track and objectify the clinical course of surgical correction of craniosynostoses. Craniofacial changes become highly reproducible and demonstrate clinical utility based on this technology.

Somatosensory Evoked Potential Monitoring during Positioning of the Patient for Posterior Fossa Surgery in the Semisitting Position

OBJECTIVE Midcervical flexion myelopathy is a rare but well-known complication of posterior fossa surgery. To reduce the risk, we routinely used somatosensory evoked potential (SSEP) monitoring during positioning of the patient. METHODS Fifty-five consecutive patients were operated on for posterior fossa lesions in the semisitting position via a median (5 patients) or a lateral (50 patients) suboccipital approach. During positioning, monitoring of SSEPs by stimulation of the tibial nerve (T-SSEP) as well as by stimulation of the median nerve (M-SSEP) was established. In the case of pronounced SSEP changes, the head was repositioned. Surgery was started after SSEP recordings were unchanged as compared to the baseline investigation. RESULTS Effective monitoring was possible in all cases. Whereas M-SSEP recordings showed no changes while placing patients in the sitting position, T-SSEP recordings were altered in 14 cases (25%). In cases using the midline approach, SSEP changes were never so pronounced to require repositioning of the head. Head flexion and rotation resulted in significant changes of T-SSEP recordings in eight patients (14.5%), requiring repositioning. In two cases, an amplitude loss was noted. In only two of these eight patients were M-SSEP recordings markedly changed. SSEP recordings after repositioning disclosed recovery of spinal cord function. In no patient were clinical signs of myelopathy observed postoperatively. CONCLUSION We observed a high incidence of pronounced changes of T-SSEP recordings when the patients head was flexed and rotated for lateral suboccipital craniotomy in the semisitting position. Despite the low specificity monitoring of T-SSEPs during positioning of the patient for posterior fossa surgery, the semisitting position is strongly recommended.

2-Octyl-cyanoacrylate for wound closure in cervical and lumbar spinal surgery

It is claimed that wound closure with 2-octyl-cyanoacrylate has the advantages that band-aids are not needed in the postoperative period, that the wound can get in contact with water and that removal of stitches is not required. This would substantially enhance patient comfort, especially in times of reduced in-hospital stays. Postoperative wound infection is a well-known complication in spinal surgery. The reported infection rates range between 0% and 12.7%. The question arises if the advantages of wound closure with 2-octyl-cyanoacrylate in spinal surgery are not surpassed by an increase in infection rate. This study has been conducted to identify the infection rate of spinal surgery if wound closure was done with 2-octyl-cyanoacrylate. A total of 235 patients with one- or two-level surgery at the cervical or lumbar spine were included in this prospective study. Their pre- and postoperative course was evaluated. Analysis included age, sex, body mass index, duration and level of operation, blood examinations, 6-week follow-up and analysis of preoperative risk factors. The data were compared to infection rates of similar surgeries found in a literature research and to a historical group of 503 patients who underwent wound closure with standard skin sutures after spine surgery. With the use of 2-octyl-cyanoacrylate, only one patient suffered from postoperative wound infection which accounts for a total infection rate of 0.43%. In the literature addressing infection rate after spine surgery, an average rate of 3.2% is reported. Infection rate was 2.2% in the historical control group. No risk factor could be identified which limited the usage of 2-octyl-cyanoacrylate. 2-Octyl-cyanoacrylate provides sufficient wound closure in spinal surgery and is associated with a low risk of postoperative wound infection.

Postoperative methemoglobinemia following infiltrative lidocaine administration for combined anesthesia in pediatric craniofacial surgery

Background:  Infiltrative anesthesia of the scalp with lidocaine was used in an attempt to reduce blood loss and anesthetic requirements during pediatric craniofacial surgery. Lidocaine, however, has the potential to cause methemoglobinemia. In this retrospective cohort‐study we analyzed the incidence and effects of postoperative methemoglobinemia following subcutaneous lidocaine administration.

High resolution imaging of craniofacial bone specimens by flat-panel volumetric computed tomography

INTRODUCTION The prototype flat-panel volumetric computed tomograph (fpvCT) provides a new 3D imaging technology with detailed high resolution by using large-area flat-panel X-ray detectors. The object of this study was to evaluate the benefit of high resolution imaging using the experimental fpvCT to visualise different types of human craniofacial bone pathology. The study proved the feasibility of performing an intraoperative evaluation of free margins in bone malignancies using fpvCT. MATERIAL AND METHODS In this study, 35 bone specimens of various pathological types were examined by fpvCT. fpvCT data were compared with pre-operative multislice clinical CT images as well as with post-operative histological findings. RESULTS Bone tumours can be visualised with their specific pathological architecture and infiltration structure faster and more precisely by fpvCT than by multislice CT. The analysis of the resection margins supports the surgical procedure intraoperatively, especially when an immediate reconstruction with bone transplantation is carried out. DISCUSSION The fpvCT has a superior image quality when compared with clinical CT systems. The imaging of the bone structure itself has been shown to be useful for the interpretation of osseous resection borders. Furthermore, it can facilitate the diagnosis of tumour progression, especially in areas that are difficult to access, such as the base of the skull.

Pathophysiology and Treatment Options in Trigeminal Meningoceles

Trigeminal meningoceles, lateral to the maxillary nerve (V2), have seldom been reported as underlying pathology for spontaneous rhinoliquorrhea. In contrast to sphenoid meningoceles arising from a persistent lateral craniopharyngeal canal (Sternberg–Cruveilhier, medial to V2), their occurrence seems to be generated by addition of erosive processes to the constitutively thin bony shell underneath the semilunar ganglion, lateral to the round foramen (and V2). The developmental and anatomical relationships of trigeminal meningoceles to the sphenoid bone are depicted, and in a review of the literature we present the different surgical approaches employed for sealing the dura leak. In view of these techniques we discuss an unusual case of therapy-resistant rhinoliquorrhea with left-sided trigeminal meningocele involving the Meckel cave at the lateral sphenoid and reaching the superior orbital fissure and the medial orbital space. In contrast to patients who have lateral sphenoidal meningoceles with a persistent lateral craniopharyngeal canal (Sternberg–Cruveilhier), who can be treated successfully using an endoscopic transsphenoidal approach (recurrence rate 13.7%), the recurrence rate of cerebrospinal fluid (CSF) efflux for trigeminal meningoceles lies much higher (endoscopically 66%, open craniotomy 33%). The surgical strategy thus has to be chosen individually, taking into account specific anatomical situations and eventually preceding operations.

Sinusoidal coronal incision.

BackgroundThe coronal incision is a standard surgical approach in craniofacial surgery. For pediatric patients, it holds a certain risk for unbeneficial aesthetic outcome due to a broadening of the scar in the fast-growing infant skull. MethodsWe readopted the coronal approach over the last decade and developed a sinusoidal type of incision based on the “stealth incision” by Munro and Fearon. We present a calculative standardization of our approach. ResultsThe sinusoidal coronal approach assures superior aesthetical results with equivalent skeletal exposure. The surgical procedure is simplified and standardized. Even in the fast-growing infant skull, broadening of the scar or vertical divergence is avoided.

Surgical correction of lambdoid synostosis – New technique and first results

OBJECTIVE Premature craniosynostosis of the lambdoid suture is rare. The use of differential diagnosis to rule out positional occipital plagiocephaly is crucial. Nevertheless, once diagnosed, lambdoid craniosynostosis requires corrective surgery to prevent intracranial harm and aesthetic stigma by significant dyscrania. Operative correction of the lambdoid fusion is often performed by suturectomy and helmet therapy, total occipital remodeling interventions, transposition of occipital bone flaps, or occipital advancement procedures either with or without distraction osteogenesis. We present a simple surgical maneuver to potentially correct the occipital and suboccipital constriction caused by unilateral lambdoid craniosynostosis. MATERIALS AND METHODS Three patients with true unilateral lambdoid synostosis underwent surgery. A straight-line skin incision was created, beginning at the caudal pole of the ipsilateral mastoideal bulge. The incision ran cranially and corresponded to the course of the lambdoid suture up to the posterior fontanel. The periosteum was incised and the contralateral (potent) lambdoid suture was identified at its origin. One burr-hole was created to separate the dura from the intern tabula. Afterwards, a square meander-shaped craniotomy was performed along the assumed course of the lambdoid suture. The squares were then forced apart to form the occipital and suboccipital area into a more rounded shape. The squares were fixed in those positions with resorbable plates or sutures. Pre- and postoperative three-dimensional (3D) photoscans were performed and analyzed with special software to follow the perioperative course of the cranial shape. RESULTS This new approach minimized the operative time and degree of blood-loss, and rounding of the occipital area was accomplished with only one unilateral intervention. In terms of the available photogrammetric data of two of the patients, the cranial vault asymmetry index, posterior symmetry ratio, and posterior/anterior skull volume ratio were improved but not normalized completely. The measurement outcome, as determined by an automated analysis of the photoscans, however, indicated clear flaws with regard to repeatability. CONCLUSION A unilateral approach using a square meander-shaped craniotomy and subsequent inclination may be a suitable surgical method for correcting assorted cases of lambdoid craniosynostosis. Transposition of the occipital bone flaps, subtotal craniectomies of the occipital area, and occipital advancements with or without distraction devices may not be essential in all cases of lambdoid synostosis. However, the reliability of the automated analysis of three-dimensional photoscans must be determined.

190. Multimodal evoked potentials in patients with subarachnoid hemorrhage

To determine its prognostic value, multimodal electrophysiological monitoring had been recorded during the management of patients suffering from subarachnoid hemorrhage (SAH). The data from 51 patients were analysed retrospectively. Initial clinical status according to the World Federation of Neurological Surgeons (WFNS-) grading system, computed tomography (CT-) findings according to Fisher grading score, endovascular vs. neurosurgical treatment, aneurysm location and clinical outcome according to Glasgow Outcome Score (GOS). Multimodal electrophysiological monitoring integrated median nerve somatosensory evoked potential (M-SSEP), tibial nerve somatosensory evoked potential (T-SSEP), visual evoked potential (VEP), brainstem auditory evoked potential (BAEP) and central conduction time (CCT) of M-SSEP. The electrophysiological data had been analysed according to an eight step system and were brought into line with the clinical data to ascertain possible prognostic statements. Clinical and electrodiagnostic findings showed a high correlation. The combined loss of T-SSEP and M-SSEP on both cortical sides had been associated with a GOS 1. None of the patients with a GOS 4 or 5 showed a loss of initial M-SSEP. Neither T-SSEP, VEP, BAEP nor CCT can be used as single valid predictor for clinical outcome. They have to be aligned and evaluated in context with the patient’s neurological status.

8. Predicting outcome after successful resuscitation using multimodal evoked potentials

Study design: For more than twenty years physicians are seeking answers to the question ‘‘how to predict an infaust or good prognosis after resuscitation?’’. This study was conducted to test the hypothesis, if the combined use of multimodal electrophysiological monitoring leads to more precise information about outcome after cardiopulmonary resuscitation (CPR) than an isolated use of each method. Data from 29 male (62%) and 18 female (32%) with an average age of 56.6 years had been analysed. Within 24–48after resuscitation N20 of M-SSEP, as well as BAEP and VEP had been examined. Glasgow Outcome Score was used to record the patient’s outcome by the time of discharge from the hospital. Results: Twenty-three (48.9%) patients died (GOS 1), 13 (57%) of them showed bilateral loss of M-SEP, three (13%) showed a loss of MSSEP on one cortical side and two (9%) patients revealed severe cortical changes. Ten patients (43.5%) who died had a normal BAEP or discrete changes after acoustic stimulation. None of the twelve patients (25.5%) who survived in good clinical condition (GOS 5 or 4), had a loss of N20, whereas five (41%) of those patients revealed severe changes of VEP. Conclusion: A loss of M-SSEP after resuscitation is a good predictor for clinical outcome. A bilateral loss of M-SEP and VEP leads to an infaust prognosis. Neither VEP nor BAEP can be used as the single valid predictor for clinical outcome. More than 30% of the patients with good recovery (GOS 5 and 4) presented with severe VEP changes and more than 40% of the patients who died, only had discrete changes or regular examinations of BAEP.