Peter J. Jannetta
Peter J. Jannetta, Mark R. Mclaughlin and Kenneth F. Casey
Vascular compression of the trigeminal nerve in the cerebellopontine angle is now generally accepted as the primary source or “trigger” causing trigeminal neuralgia. A clear clinicopathological association exists in the neurovascular relationship. In general, pain in the third division of the trigeminal nerve is caused by rostral compression, pain in the second division is caused by medial or more distant compression, and pain in the first division is caused by caudal compression.
This discussion of the surgical technique includes details on patient position, placement of the incision and craniectomy, microsurgical exposure of the supralateral cerebellopontine angle, visualization of the trigeminal nerve and vascular pathological features, microvascular decompression, and wound closure. Nuances of the technique are best learned in the company of a surgeon who has a longer experience with this procedure.
Mark R. McLaughlin, Peter J. Jannetta, Brent L. Clyde, Brian R. Subach, Christopher H. Comey and Daniel K. Resnick
Microvascular decompression has become an accepted surgical technique for the treatment of trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, and other cranial nerve rhizopathies. The senior author (P.J.J.) began performing this procedure in 1969 and has performed more than 4400 operations. The purpose of this article is to review some of the nuances of the technical aspects of this procedure.
A review of 4415 operations shows that numerous modifications to the technique of microvascular decompression have occurred during the last 29 years. Of the 2420 operations performed for trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia before 1990, cerebellar injury occurred in 21 cases (0.87%), hearing loss in 48 (1.98%), and cerebrospinal fluid (CSF) leakage in 59 cases (2.44%). Of the 1995 operations performed since 1990, cerebellar injuries declined to nine cases (0.45%), hearing loss to 16 (0.8%), and CSF leakage to 37 (1.85%) (p < 0.01, test for equality of distributions). The authors describe slight variations made to maximize surgical exposure and minimize potential complications in each of the six principal steps of this operation. These modifications have led to decreasing complication rates in recent years.
Using the techniques described in this report, microvascular decompression is an extremely safe and effective treatment for many cranial nerve rhizopathies.
Raymond F. Sekula Jr., Sanjay Bhatia, Andrew M. Frederickson, Peter J. Jannetta, Matthew R. Quigley, George A. Small and Ryan Breisinger
In this paper, the authors' goal was to determine the utility of monitoring the abnormal muscle response (AMR) or “lateral spread” during microvascular decompression surgery for hemifacial spasm.
The authors' experience with AMR as well as the data available in the English-language literature regarding resolution or persistence of AMR and the resolution or persistence of hemifacial spasm at follow-up was pooled and subjected to a meta-analysis.
The pooled OR revealed by the meta-analysis was 4.2 (95% CI 2.7–6.7). The chance of a cure if the AMR was abolished during surgery was 4.2 times greater than if the lateral spread persisted.
The AMR should be monitored routinely in the operating room, and surgical decision-making in the operating room should be augmented by the AMR.
Raymond F. Sekula Jr., Andrew M. Frederickson, Peter J. Jannetta, Sanjay Bhatia, Matthew R. Quigley and Khaled M. Abdel Aziz
The authors have the clinical impression that patients with isolated V2, or maxillary division, trigeminal neuralgia (TN) are most often women of a younger age with atypical pain features and a predominance of venous compression as the pathology. The aim of this study was to evaluate a specific subgroup of patients with V2 TN.
Among 120 patients who underwent microvascular decompression (MVD) for TN in 2007, data were available for 114; 6 patients were lost to follow-up. Patients were stratified according to typical (Burchiel Type 1), mixed (Burchiel Type 2a), or atypical (Burchiel Type 2b) TN. A pain-free status without medication was used to determine the efficacy of MVD. All patients were contacted in June 2008 and again in January 2009 at 12–24 months after surgery (median 18.4 months) and asked to rate their response to MVD as excellent (complete pain relief without medication), fair (complete pain relief with medication or some relief with or without medication), or poor (continued pain despite medication; that is, no change from their preoperative baseline pain status.
Of 114 patients, 14 (12%) had isolated V2 TN. Among these 14 were 2 typical (14%), 1 mixed (7%), and 11 atypical cases (79%) of TN. Among the remaining 100 cases were 37 typical (37%), 14 mixed (14%), and 49 atypical cases (49%) of TN. In the isolated V2 TN group, all patients were women as compared with 72% of women in the larger group of 100 patients (p = 0.05, chi-square test). The average age in the isolated V2 TN group was 51.2 years (median 48.1 years) versus 54.2 years (median 54.0 years) in the remainder of the group (p = NS, unpaired Student t-test). In the isolated V2 TN group, there was a predominance of atypical pain cases (79%) versus 49% in the remainder of the group, and this finding trended toward statistical significance (p = 0.07, chi-square test). Venous contact or compression (partly or wholly) was noted in 93% of the patients with isolated V2 versus 69% of the remainder of the group (p = 0.13, chi-square test). The likelihood of excellent outcomes in the patients with V2 TN (71%) was compared with that in typical pain cases (79%) among patients in the rest of the group (that is, the bestoutcome group), and no difference was found between the 2 groups (p = 0.8, chi-square test).
The authors confirmed that patients with isolated V2 TN were more likely to be female, tended toward an atypical pain classification with venous pathology at surgery, and fared just as well as those presenting with typical pain.